diff --git a/.travis.yml b/.travis.yml
index 6d25e64..84a6e1e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,13 +21,13 @@ before_script:
   - cp gradle.properties.ci.example gradle.properties
   # Emulator Management: Create, Start and Wait
   - echo no | android create avd --force -n test -t android-22 --abi armeabi-v7a
-  - emulator -avd test -no-skin -no-audio -no-window &
+  - emulator -avd test -no-audio -no-window &
   - android-wait-for-emulator
   - adb shell input keyevent 82 &
 
 script:
-  - ./gradlew clean connectedAndroidTest --info
-  - ./gradlew testDebugUnitTest --info
+  - ./gradlew clean connectedAndroidTest
+  - ./gradlew testDebugUnitTest
 
 before_cache:
   - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
diff --git a/README.md b/README.md
index 0a29f57..42e891a 100644
--- a/README.md
+++ b/README.md
@@ -1,18 +1,16 @@
 # Android micropost app
 
-This repository is an example Android application, which is based on Rails tutorial app.
+This repository is an example Android application based on Rails tutorial app.
 
 [![Build Status](https://travis-ci.org/springboot-angular2-tutorial/android-app.svg?branch=master)](https://travis-ci.org/springboot-angular2-tutorial/android-app)
-[![Coverage Status](https://coveralls.io/repos/github/springboot-angular2-tutorial/android-app/badge.svg?branch=master)](https://coveralls.io/github/springboot-angular2-tutorial/android-app?branch=master)
 
-Key components.
-
-* Dagger 2
-* Retrolambda
-* RxJava / RxAndroid
-* Retrofit 2
-* Data Binding
-* Robolectric 3
+* Kotlin 100% without kapt
+* [Kodein](https://github.com/SalomonBrys/Kodein) as Dependency Injection
+* [RxJava](https://github.com/ReactiveX/RxJava) / [RxAndroid](https://github.com/ReactiveX/RxAndroid)
+* [RxBinding](https://github.com/JakeWharton/RxBinding)
+* [Retrofit](https://github.com/square/retrofit)
+* [Robolectric](http://robolectric.org/) for testing model layer
+* [Espresso](https://google.github.io/android-testing-support-library/docs/espresso/) for testing presentation layer
 
 ## Getting Started
 
@@ -40,7 +38,8 @@ Then, just run from Android Studio.
 Testing.
 
 ```
-./gradlew testDebug
+./gradlew testDebugUnitTest
+./gradlew connectedAndroidTest
 ```
 
 Release build.
diff --git a/app/build.gradle b/app/build.gradle
index c762b48..9ecd999 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -12,7 +12,7 @@ android {
         targetSdkVersion 25
         versionCode 1
         versionName "1.0.0"
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunner "com.hana053.micropost.testing.AppTestRunner"
         multiDexEnabled = true
         buildConfigField('String', 'API_URL', getProperty("micropost.apiUrl"))
     }
@@ -44,9 +44,6 @@ android {
         androidTest.java.srcDirs += 'src/androidTest/kotlin'
         androidTest.java.srcDirs += 'src/testShared/kotlin'
     }
-    dexOptions {
-        javaMaxHeapSize '2g'
-    }
     configurations.all {
         resolutionStrategy.force 'com.google.code.findbugs:jsr305:3.0.1'
     }
@@ -69,11 +66,11 @@ dependencies {
     compile "com.squareup.retrofit2:retrofit:$retrofit_version"
     compile "com.squareup.retrofit2:adapter-rxjava:$retrofit_version"
     compile "com.squareup.retrofit2:converter-moshi:$retrofit_version"
-    compile 'com.squareup.okhttp3:okhttp:3.6.0'
-    compile 'com.squareup.picasso:picasso:2.5.2'
-    compile 'com.jakewharton.timber:timber:4.3.1'
-    compile 'com.github.curioustechizen.android-ago:library:1.3.2'
-    compile group: 'com.nimbusds', name: 'nimbus-jose-jwt', version: '4.34'
+    compile "com.squareup.okhttp3:okhttp:$okhttp_version"
+    compile "com.squareup.picasso:picasso:$picasso_version"
+    compile "com.jakewharton.timber:timber:$timber_version"
+    compile "com.github.curioustechizen.android-ago:library:$android_ago_version"
+    compile "com.nimbusds:nimbus-jose-jwt:$jose_jwt_version"
 
     debugCompile "com.squareup.leakcanary:leakcanary-android:$leakcanary_version"
 
@@ -84,6 +81,7 @@ dependencies {
     testCompile "org.robolectric:robolectric:$robolectric_version"
     testCompile "org.robolectric:shadows-support-v4:$robolectric_version"
     testCompile "com.squareup.leakcanary:leakcanary-android-no-op:$leakcanary_version"
+    testCompile group: 'org.assertj', name: 'assertj-core', version: assertj_version
 
     androidTestCompile "com.android.support.test:runner:$android_support_test_version"
     androidTestCompile "com.android.support.test:rules:$android_support_test_version"
@@ -93,8 +91,10 @@ dependencies {
     androidTestCompile "com.android.support:support-annotations:$android_support_version"
     androidTestCompile "org.mockito:mockito-core:$mockito_version"
     androidTestCompile "com.nhaarman:mockito-kotlin:$mockito_kotlin_version"
-    androidTestCompile 'com.linkedin.dexmaker:dexmaker-mockito:2.2.0'
+    androidTestCompile "com.linkedin.dexmaker:dexmaker-mockito:$dexmaker_mockito_version"
     androidTestCompile "com.squareup.leakcanary:leakcanary-android-no-op:$leakcanary_version"
+    androidTestCompile "com.linkedin.testbutler:test-butler-library:$testbutler_version"
+    androidTestCompile "com.squareup.assertj:assertj-android:$assertj_android_version"
 }
 repositories {
     mavenCentral()
diff --git a/app/jacoco.gradle b/app/jacoco.gradle
deleted file mode 100644
index 2e22f2b..0000000
--- a/app/jacoco.gradle
+++ /dev/null
@@ -1,47 +0,0 @@
-apply plugin: 'jacoco'
-
-jacoco {
-    // https://bintray.com/bintray/jcenter/org.jacoco:org.jacoco.core
-    toolVersion = "0.7.7.201606060606"
-}
-
-android {
-    testOptions {
-        unitTests.all {
-            jacoco {
-                includeNoLocationClasses = true
-            }
-        }
-    }
-}
-
-project.afterEvaluate {
-
-    android.applicationVariants.all { variant ->
-        def name = variant.name
-        def testTaskName = "test${name.capitalize()}UnitTest"
-
-        tasks.create(name: "${testTaskName}Coverage", type: JacocoReport, dependsOn: "$testTaskName") {
-            group = "Reporting"
-            description = "Generate Jacoco coverage reports for the ${name.capitalize()} build."
-
-            classDirectories = fileTree(
-                    dir: "${project.buildDir}/intermediates/classes/${name}",
-                    excludes: ['**/R.class',
-                               '**/R$*.class',
-                               '**/*$ViewInjector*.*',
-                               '**/*$ViewBinder*.*',
-                               '**/BuildConfig.*',
-                               '**/Manifest*.*']
-            )
-
-            sourceDirectories = files(['src/main/java'].plus(android.sourceSets[name].java.srcDirs))
-            executionData = files("${project.buildDir}/jacoco/${testTaskName}.exec")
-
-            reports {
-                xml.enabled = true
-                html.enabled = true
-            }
-        }
-    }
-}
\ No newline at end of file
diff --git a/app/src/androidTest/kotlin/com/hana053/micropost/pages/login/LoginActivityTest.kt b/app/src/androidTest/kotlin/com/hana053/micropost/pages/login/LoginActivityTest.kt
index 01ea514..9c28d8e 100644
--- a/app/src/androidTest/kotlin/com/hana053/micropost/pages/login/LoginActivityTest.kt
+++ b/app/src/androidTest/kotlin/com/hana053/micropost/pages/login/LoginActivityTest.kt
@@ -35,9 +35,9 @@ class LoginActivityTest : InjectableTest by InjectableTestImpl() {
     @Rule @JvmField
     val activityRule = ActivityTestRule(LoginActivity::class.java, false, false)
 
-    val loginBtn: Matcher<View> = withId(R.id.loginBtn)
-    val emailEditText: Matcher<View> = withId(R.id.emailEditText)
-    val passwordEditText: Matcher<View> = withId(R.id.passwordEditText)
+    val loginBtn: Matcher<View> = withId(R.id.btn_login)
+    val emailEditText: Matcher<View> = withId(R.id.et_email)
+    val passwordEditText: Matcher<View> = withId(R.id.et_password)
 
     @Test
     fun shouldBeOpened() {
diff --git a/app/src/androidTest/kotlin/com/hana053/micropost/pages/main/MainActivityTest.kt b/app/src/androidTest/kotlin/com/hana053/micropost/pages/main/MainActivityTest.kt
index 5bd731b..040db9b 100644
--- a/app/src/androidTest/kotlin/com/hana053/micropost/pages/main/MainActivityTest.kt
+++ b/app/src/androidTest/kotlin/com/hana053/micropost/pages/main/MainActivityTest.kt
@@ -70,8 +70,8 @@ class MainActivityTest : InjectableTest by InjectableTestImpl() {
 
         activityRule.launchActivity(null)
 
-        onView(withId(R.id.postRecyclerView))
-            .check(matches(atPositionOnView(0, withText("my test content"), R.id.content)))
+        onView(withId(R.id.list_post))
+            .check(matches(atPositionOnView(0, withText("my test content"), R.id.tv_post_content)))
     }
 
     @Test
@@ -91,12 +91,12 @@ class MainActivityTest : InjectableTest by InjectableTestImpl() {
         }
 
         activityRule.launchActivity(null)
-        onView(withId(R.id.swipeRefreshLayout)).perform(swipeDown())
+        onView(withId(R.id.swipe_refresh)).perform(swipeDown())
 
-        onView(withId(R.id.postRecyclerView))
-            .check(matches(atPositionOnView(0, withText("my new content"), R.id.content)))
-        onView(withId(R.id.postRecyclerView))
-            .check(matches(atPositionOnView(1, withText("my test content"), R.id.content)))
+        onView(withId(R.id.list_post))
+            .check(matches(atPositionOnView(0, withText("my new content"), R.id.tv_post_content)))
+        onView(withId(R.id.list_post))
+            .check(matches(atPositionOnView(1, withText("my test content"), R.id.tv_post_content)))
     }
 
     @Test
@@ -117,10 +117,10 @@ class MainActivityTest : InjectableTest by InjectableTestImpl() {
 
         activityRule.launchActivity(null)
 
-        onView(withId(R.id.postRecyclerView))
-            .check(matches(atPositionOnView(0, withText("my test content"), R.id.content)))
-        onView(withId(R.id.postRecyclerView))
-            .check(matches(atPositionOnView(1, withText("my old content"), R.id.content)))
+        onView(withId(R.id.list_post))
+            .check(matches(atPositionOnView(0, withText("my test content"), R.id.tv_post_content)))
+        onView(withId(R.id.list_post))
+            .check(matches(atPositionOnView(1, withText("my old content"), R.id.tv_post_content)))
     }
 
     @Test
@@ -139,7 +139,7 @@ class MainActivityTest : InjectableTest by InjectableTestImpl() {
         }
 
         activityRule.launchActivity(null)
-        onView(withId(R.id.avatar)).perform(click())
+        onView(withId(R.id.img_avatar)).perform(click())
 
         verify(navigator).navigateToUserShow(1)
     }
@@ -158,7 +158,7 @@ class MainActivityTest : InjectableTest by InjectableTestImpl() {
         }
 
         activityRule.launchActivity(null)
-        onView(withId(R.id.newMicropostBtn)).perform(click())
+        onView(withId(R.id.btn_new_micropost)).perform(click())
 
         verify(navigator).navigateToMicropostNew()
     }
@@ -180,9 +180,9 @@ class MainActivityTest : InjectableTest by InjectableTestImpl() {
         activityRule.launchActivity(null)
         verify(feedInteractor, times(1)).loadNextFeed(null)
 
-        onView(withId(R.id.newMicropostBtn)).perform(click())
-        onView(withId(R.id.postEditText)).perform(typeText("hello"))
-        onView(withId(R.id.postBtn)).perform(closeSoftKeyboard(), click())
+        onView(withId(R.id.btn_new_micropost)).perform(click())
+        onView(withId(R.id.et_post)).perform(typeText("hello"))
+        onView(withId(R.id.btn_post)).perform(closeSoftKeyboard(), click())
 
         verify(feedInteractor, times(2)).loadNextFeed(null)
     }
diff --git a/app/src/androidTest/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewActivityTest.kt b/app/src/androidTest/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewActivityTest.kt
index ab4cbaf..3201976 100644
--- a/app/src/androidTest/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewActivityTest.kt
+++ b/app/src/androidTest/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewActivityTest.kt
@@ -1,5 +1,6 @@
 package com.hana053.micropost.pages.micropostnew
 
+import org.assertj.android.api.Assertions.assertThat
 import android.support.test.espresso.Espresso.onView
 import android.support.test.espresso.action.ViewActions.*
 import android.support.test.espresso.assertion.ViewAssertions.matches
@@ -20,7 +21,6 @@ import com.nhaarman.mockito_kotlin.any
 import com.nhaarman.mockito_kotlin.doReturn
 import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
-import org.hamcrest.CoreMatchers.`is`
 import org.hamcrest.CoreMatchers.not
 import org.junit.Rule
 import org.junit.Test
@@ -57,10 +57,10 @@ class MicropostNewActivityTest : InjectableTest by InjectableTestImpl() {
         overrideAppBindings { fakeAuthToken() }
         activityRule.launchActivity(null)
 
-        onView(withId(R.id.postBtn)).check(matches(not(isEnabled())))
+        onView(withId(R.id.btn_post)).check(matches(not(isEnabled())))
 
-        onView(withId(R.id.postEditText)).perform(typeText("a"))
-        onView(withId(R.id.postBtn)).check(matches(isEnabled()))
+        onView(withId(R.id.et_post)).perform(typeText("a"))
+        onView(withId(R.id.btn_post)).check(matches(isEnabled()))
     }
 
     @Test
@@ -74,11 +74,11 @@ class MicropostNewActivityTest : InjectableTest by InjectableTestImpl() {
         }
         activityRule.launchActivity(null)
 
-        onView(withId(R.id.postEditText)).perform(typeText("a"))
-        onView(withId(R.id.postBtn)).perform(closeSoftKeyboard(), click())
+        onView(withId(R.id.et_post)).perform(typeText("a"))
+        onView(withId(R.id.btn_post)).perform(closeSoftKeyboard(), click())
 
         verify(micropostInteractor).create(MicropostInteractor.MicropostRequest("a"))
-        assertThat(activityRule.activity.isFinishing, `is`(true))
+        assertThat(activityRule.activity).isFinishing
     }
 
 }
\ No newline at end of file
diff --git a/app/src/androidTest/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListActivityTest.kt b/app/src/androidTest/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListActivityTest.kt
index 53efc87..a15a6cb 100644
--- a/app/src/androidTest/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListActivityTest.kt
+++ b/app/src/androidTest/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListActivityTest.kt
@@ -22,7 +22,6 @@ import com.nhaarman.mockito_kotlin.anyOrNull
 import com.nhaarman.mockito_kotlin.doReturn
 import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
-import org.hamcrest.CoreMatchers.allOf
 import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -48,10 +47,7 @@ class RelatedUserListActivityTest : InjectableTest by InjectableTestImpl() {
             })
         }
         launchActivity(FOLLOWER, 1)
-        onView(allOf(
-            isDescendantOfA(withResourceName("android:id/action_bar_container")),
-            withText(R.string.Followers)
-        ))
+        onView(withText(R.string.Followers)).check(matches(isDisplayed()))
     }
 
     @Test
@@ -78,8 +74,8 @@ class RelatedUserListActivityTest : InjectableTest by InjectableTestImpl() {
         }
         launchActivity(FOLLOWER, 1)
 
-        onView(withId(R.id.userRecyclerView))
-            .check(matches(atPositionOnView(0, withText("John Doe"), R.id.userName)))
+        onView(withId(R.id.list_user))
+            .check(matches(atPositionOnView(0, withText("John Doe"), R.id.tv_user_name)))
     }
 
     @Test
@@ -99,10 +95,10 @@ class RelatedUserListActivityTest : InjectableTest by InjectableTestImpl() {
         }
         launchActivity(FOLLOWER, 1)
 
-        onView(withId(R.id.userRecyclerView))
-            .check(matches(atPositionOnView(0, withText("John Doe"), R.id.userName)))
-        onView(withId(R.id.userRecyclerView))
-            .check(matches(atPositionOnView(1, withText("Old Follower"), R.id.userName)))
+        onView(withId(R.id.list_user))
+            .check(matches(atPositionOnView(0, withText("John Doe"), R.id.tv_user_name)))
+        onView(withId(R.id.list_user))
+            .check(matches(atPositionOnView(1, withText("Old Follower"), R.id.tv_user_name)))
     }
 
     @Test
@@ -126,8 +122,8 @@ class RelatedUserListActivityTest : InjectableTest by InjectableTestImpl() {
         }
         launchActivity(FOLLOWER, 1)
 
-        onView(withId(R.id.followBtn)).perform(click())
-        onView(withId(R.id.followBtn)).check(matches(withText(R.string.Unfollow)))
+        onView(withId(R.id.btn_follow)).perform(click())
+        onView(withId(R.id.btn_follow)).check(matches(withText(R.string.Unfollow)))
     }
 
     @Test
@@ -145,7 +141,7 @@ class RelatedUserListActivityTest : InjectableTest by InjectableTestImpl() {
             bind<Navigator>(overrides = true) with instance(navigator)
         }
         launchActivity(FOLLOWER, 1)
-        onView(withId(R.id.avatar)).perform(click())
+        onView(withId(R.id.img_avatar)).perform(click())
 
         verify(navigator).navigateToUserShow(100)
     }
@@ -162,10 +158,7 @@ class RelatedUserListActivityTest : InjectableTest by InjectableTestImpl() {
             })
         }
         launchActivity(FOLLOWING, 1)
-        onView(allOf(
-            isDescendantOfA(withResourceName("android:id/action_bar_container")),
-            withText(R.string.Followings)
-        ))
+        onView(withText(R.string.Followings)).check(matches(isDisplayed()))
     }
 
     @Test
@@ -182,8 +175,8 @@ class RelatedUserListActivityTest : InjectableTest by InjectableTestImpl() {
         }
         launchActivity(FOLLOWING, 1)
 
-        onView(withId(R.id.userRecyclerView))
-            .check(matches(atPositionOnView(0, withText("John Doe"), R.id.userName)))
+        onView(withId(R.id.list_user))
+            .check(matches(atPositionOnView(0, withText("John Doe"), R.id.tv_user_name)))
     }
 
     private fun launchActivity(listType: RelatedUserListActivity.ListType, userId: Long) {
diff --git a/app/src/androidTest/kotlin/com/hana053/micropost/pages/signup/SignupActivityTest.kt b/app/src/androidTest/kotlin/com/hana053/micropost/pages/signup/SignupActivityTest.kt
index 965a20a..d4fc763 100644
--- a/app/src/androidTest/kotlin/com/hana053/micropost/pages/signup/SignupActivityTest.kt
+++ b/app/src/androidTest/kotlin/com/hana053/micropost/pages/signup/SignupActivityTest.kt
@@ -7,6 +7,7 @@ import android.support.test.espresso.matcher.ViewMatchers.*
 import android.support.test.filters.LargeTest
 import android.support.test.rule.ActivityTestRule
 import android.support.test.runner.AndroidJUnit4
+import android.view.View
 import com.github.salomonbrys.kodein.bind
 import com.github.salomonbrys.kodein.instance
 import com.hana053.micropost.R
@@ -24,13 +25,15 @@ import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
 import kotlinx.android.synthetic.main.fragment_signup_email.*
 import kotlinx.android.synthetic.main.fragment_signup_full_name.*
-import org.hamcrest.CoreMatchers.`is`
+import org.assertj.android.api.Assertions.assertThat
+import org.hamcrest.CoreMatchers.allOf
 import org.hamcrest.CoreMatchers.not
+import org.hamcrest.Matcher
 import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
+import retrofit2.HttpException
 import retrofit2.Response
-import retrofit2.adapter.rxjava.HttpException
 import rx.Observable
 
 
@@ -41,6 +44,19 @@ class SignupActivityTest : InjectableTest by InjectableTestImpl() {
     @Rule @JvmField
     val activityRule = ActivityTestRule(SignupActivity::class.java, false, false)
 
+    val fullNameNextBtn: Matcher<View> = allOf(
+        withId(R.id.btn_next),
+        isDescendantOfA(withId(R.id.fragment_signup_full_name))
+    )
+    val emailNextBtn: Matcher<View> = allOf(
+        withId(R.id.btn_next),
+        isDescendantOfA(withId(R.id.fragment_signup_email))
+    )
+    val passwordNextBtn: Matcher<View> = allOf(
+        withId(R.id.btn_next),
+        isDescendantOfA(withId(R.id.fragment_signup_password))
+    )
+
     @Test
     fun shouldBeOpened() {
         activityRule.launchActivity(null)
@@ -51,18 +67,18 @@ class SignupActivityTest : InjectableTest by InjectableTestImpl() {
     fun shouldInputName() {
         activityRule.launchActivity(null)
 
-        onView(withId(R.id.fullNameNextBtn)).check(matches(not(isEnabled())))
-        onView(withId(R.id.fullNameInvalid)).check(matches(not(isDisplayed())))
+        onView(fullNameNextBtn).check(matches(not(isEnabled())))
+        onView(withId(R.id.tv_full_name_invalid)).check(matches(not(isDisplayed())))
 
-        onView(withId(R.id.fullName)).perform(typeText("a"), closeSoftKeyboard())
-        onView(withId(R.id.fullNameInvalid)).check(matches(isDisplayed()))
-        onView(withId(R.id.fullNameNextBtn)).check(matches(not(isEnabled())))
+        onView(withId(R.id.et_full_name)).perform(typeText("a"), closeSoftKeyboard())
+        onView(withId(R.id.tv_full_name_invalid)).check(matches(isDisplayed()))
+        onView(fullNameNextBtn).check(matches(not(isEnabled())))
 
-        onView(withId(R.id.fullName)).perform(replaceText("John Doe"), closeSoftKeyboard())
-        onView(withId(R.id.fullNameNextBtn)).check(matches(isEnabled()))
-        onView(withId(R.id.fullNameInvalid)).check(matches(not(isDisplayed())))
+        onView(withId(R.id.et_full_name)).perform(replaceText("John Doe"), closeSoftKeyboard())
+        onView(fullNameNextBtn).check(matches(isEnabled()))
+        onView(withId(R.id.tv_full_name_invalid)).check(matches(not(isDisplayed())))
 
-        onView(withId(R.id.fullNameNextBtn)).perform(click())
+        onView(fullNameNextBtn).perform(click())
         onView(withText(R.string.what_s_your_email)).check(matches(isDisplayed()))
     }
 
@@ -72,18 +88,18 @@ class SignupActivityTest : InjectableTest by InjectableTestImpl() {
 
         moveToEmailWithName("John Doe")
 
-        onView(withId(R.id.emailNextBtn)).check(matches(not(isEnabled())))
-        onView(withId(R.id.emailInvalid)).check(matches(not(isDisplayed())))
+        onView(emailNextBtn).check(matches(not(isEnabled())))
+        onView(withId(R.id.tv_email_invalid)).check(matches(not(isDisplayed())))
 
-        onView(withId(R.id.email)).perform(typeText("a"), closeSoftKeyboard())
-        onView(withId(R.id.emailInvalid)).check(matches(isDisplayed()))
-        onView(withId(R.id.emailNextBtn)).check(matches(not(isEnabled())))
+        onView(withId(R.id.et_email)).perform(typeText("a"), closeSoftKeyboard())
+        onView(withId(R.id.tv_email_invalid)).check(matches(isDisplayed()))
+        onView(emailNextBtn).check(matches(not(isEnabled())))
 
-        onView(withId(R.id.email)).perform(replaceText("test@test.com"), closeSoftKeyboard())
-        onView(withId(R.id.emailNextBtn)).check(matches(isEnabled()))
-        onView(withId(R.id.emailInvalid)).check(matches(not(isDisplayed())))
+        onView(withId(R.id.et_email)).perform(replaceText("test@test.com"), closeSoftKeyboard())
+        onView(emailNextBtn).check(matches(isEnabled()))
+        onView(withId(R.id.tv_email_invalid)).check(matches(not(isDisplayed())))
 
-        onView(withId(R.id.emailNextBtn)).perform(click())
+        onView(emailNextBtn).perform(click())
         onView(withText(R.string.you_ll_need_a_password)).check(matches(isDisplayed()))
     }
 
@@ -104,18 +120,18 @@ class SignupActivityTest : InjectableTest by InjectableTestImpl() {
         moveToEmailWithName("John Doe")
         moveToPasswordWithEmail("test@test.com")
 
-        onView(withId(R.id.passwordNextBtn)).check(matches(not(isEnabled())))
-        onView(withId(R.id.passwordInvalid)).check(matches(not(isDisplayed())))
+        onView(passwordNextBtn).check(matches(not(isEnabled())))
+        onView(withId(R.id.tv_password_invalid)).check(matches(not(isDisplayed())))
 
-        onView(withId(R.id.password)).perform(typeText("a"), closeSoftKeyboard())
-        onView(withId(R.id.passwordInvalid)).check(matches(isDisplayed()))
-        onView(withId(R.id.passwordNextBtn)).check(matches(not(isEnabled())))
+        onView(withId(R.id.et_password)).perform(typeText("a"), closeSoftKeyboard())
+        onView(withId(R.id.tv_password_invalid)).check(matches(isDisplayed()))
+        onView(passwordNextBtn).check(matches(not(isEnabled())))
 
-        onView(withId(R.id.password)).perform(replaceText("secret123"), closeSoftKeyboard())
-        onView(withId(R.id.passwordNextBtn)).check(matches(isEnabled()))
-        onView(withId(R.id.passwordInvalid)).check(matches(not(isDisplayed())))
+        onView(withId(R.id.et_password)).perform(replaceText("secret123"), closeSoftKeyboard())
+        onView(passwordNextBtn).check(matches(isEnabled()))
+        onView(withId(R.id.tv_password_invalid)).check(matches(not(isDisplayed())))
 
-        onView(withId(R.id.passwordNextBtn)).perform(click())
+        onView(passwordNextBtn).perform(click())
 
         verify(navigator).navigateToMain()
     }
@@ -147,26 +163,26 @@ class SignupActivityTest : InjectableTest by InjectableTestImpl() {
 
         onView(withId(android.R.id.content)).perform(pressBack())
         onView(withText(R.string.what_s_your_email)).check(matches(isDisplayed()))
-        assertThat(activity.email.text.toString(), `is`("test@test.com"))
+        assertThat(activity.et_email).hasTextString("test@test.com")
 
         onView(withId(android.R.id.content)).perform(pressBack())
         onView(withText(R.string.hi_what_s_your_name)).check(matches(isDisplayed()))
-        assertThat(activity.fullName.text.toString(), `is`("John Doe"))
+        assertThat(activity.et_full_name).hasTextString("John Doe")
     }
 
     private fun moveToEmailWithName(name: String) {
-        onView(withId(R.id.fullName)).perform(typeText(name), closeSoftKeyboard())
-        onView(withId(R.id.fullNameNextBtn)).perform(click())
+        onView(withId(R.id.et_full_name)).perform(typeText(name), closeSoftKeyboard())
+        onView(fullNameNextBtn).perform(click())
     }
 
     private fun moveToPasswordWithEmail(email: String) {
-        onView(withId(R.id.email)).perform(typeText(email), closeSoftKeyboard())
-        onView(withId(R.id.emailNextBtn)).perform(click())
+        onView(withId(R.id.et_email)).perform(typeText(email), closeSoftKeyboard())
+        onView(emailNextBtn).perform(click())
     }
 
     private fun moveToMainWithPassword(password: String) {
-        onView(withId(R.id.password)).perform(typeText(password), closeSoftKeyboard())
-        onView(withId(R.id.passwordNextBtn)).perform(click())
+        onView(withId(R.id.et_password)).perform(typeText(password), closeSoftKeyboard())
+        onView(passwordNextBtn).perform(click())
     }
 
 }
\ No newline at end of file
diff --git a/app/src/androidTest/kotlin/com/hana053/micropost/pages/top/TopActivityTest.kt b/app/src/androidTest/kotlin/com/hana053/micropost/pages/top/TopActivityTest.kt
index 80cb03b..1ee4c3e 100644
--- a/app/src/androidTest/kotlin/com/hana053/micropost/pages/top/TopActivityTest.kt
+++ b/app/src/androidTest/kotlin/com/hana053/micropost/pages/top/TopActivityTest.kt
@@ -42,7 +42,7 @@ class TopActivityTest : InjectableTest by InjectableTestImpl() {
         }
 
         activityRule.launchActivity(null)
-        onView(withId(R.id.signupBtn)).perform(click())
+        onView(withId(R.id.btn_signup)).perform(click())
 
         verify(navigator).navigateToSignup()
     }
@@ -55,7 +55,7 @@ class TopActivityTest : InjectableTest by InjectableTestImpl() {
         }
 
         activityRule.launchActivity(null)
-        onView(withId(R.id.loginBtn)).perform(click())
+        onView(withId(R.id.btn_login)).perform(click())
 
         verify(navigator).navigateToLogin()
     }
diff --git a/app/src/androidTest/kotlin/com/hana053/micropost/pages/usershow/UserShowActivityTest.kt b/app/src/androidTest/kotlin/com/hana053/micropost/pages/usershow/UserShowActivityTest.kt
index d98c015..7d9acde 100644
--- a/app/src/androidTest/kotlin/com/hana053/micropost/pages/usershow/UserShowActivityTest.kt
+++ b/app/src/androidTest/kotlin/com/hana053/micropost/pages/usershow/UserShowActivityTest.kt
@@ -4,7 +4,8 @@ import android.content.Intent
 import android.support.test.espresso.Espresso.onView
 import android.support.test.espresso.action.ViewActions.click
 import android.support.test.espresso.assertion.ViewAssertions.matches
-import android.support.test.espresso.matcher.ViewMatchers.*
+import android.support.test.espresso.matcher.ViewMatchers.withId
+import android.support.test.espresso.matcher.ViewMatchers.withText
 import android.support.test.filters.LargeTest
 import android.support.test.rule.ActivityTestRule
 import android.support.test.runner.AndroidJUnit4
@@ -41,8 +42,6 @@ class UserShowActivityTest : InjectableTest by InjectableTestImpl() {
             fakeLoadingDetail()
         }
         launchActivityWithUserId(1)
-        onView(withText(R.string.followers)).check(matches(isDisplayed()))
-        onView(withText(R.string.followings)).check(matches(isDisplayed()))
     }
 
     @Test
@@ -67,7 +66,7 @@ class UserShowActivityTest : InjectableTest by InjectableTestImpl() {
             })
         }
         launchActivityWithUserId(1)
-        onView(withText("John Doe")).check(matches(isDisplayed()))
+        onView(withId(R.id.tv_user_name)).check(matches(withText("John Doe")))
     }
 
     @Test
@@ -91,14 +90,14 @@ class UserShowActivityTest : InjectableTest by InjectableTestImpl() {
         }
 
         launchActivityWithUserId(1)
-        onView(withId(R.id.followBtn)).check(matches(withText(R.string.Follow)))
+        onView(withId(R.id.btn_follow)).check(matches(withText(R.string.Follow)))
 
         // Do Follow. It will finally fetch user again.
         `when`(userInteractor.get(1)).thenReturn(Observable.just(
             TestUser.copy(name = "John Doe", isFollowedByMe = true)
         ))
-        onView(withId(R.id.followBtn)).perform(click())
-        onView(withId(R.id.followBtn)).check(matches(withText(R.string.Unfollow)))
+        onView(withId(R.id.btn_follow)).perform(click())
+        onView(withId(R.id.btn_follow)).check(matches(withText(R.string.Unfollow)))
     }
 
     @Test
@@ -112,7 +111,7 @@ class UserShowActivityTest : InjectableTest by InjectableTestImpl() {
         }
 
         launchActivityWithUserId(1)
-        onView(withId(R.id.followers)).perform(click())
+        onView(withId(R.id.tv_followers)).perform(click())
 
         verify(navigator).navigateToFollowerList(1)
     }
@@ -128,7 +127,7 @@ class UserShowActivityTest : InjectableTest by InjectableTestImpl() {
         }
 
         launchActivityWithUserId(1)
-        onView(withId(R.id.followings)).perform(click())
+        onView(withId(R.id.tv_followings)).perform(click())
 
         verify(navigator).navigateToFollowingList(1)
     }
@@ -149,8 +148,8 @@ class UserShowActivityTest : InjectableTest by InjectableTestImpl() {
 
         launchActivityWithUserId(1)
 
-        onView(withId(R.id.postRecyclerView))
-            .check(matches(atPositionOnView(0, withText("my test content"), R.id.content)))
+        onView(withId(R.id.list_post))
+            .check(matches(atPositionOnView(0, withText("my test content"), R.id.tv_post_content)))
     }
 
     private fun launchActivityWithUserId(userId: Long) {
@@ -159,7 +158,7 @@ class UserShowActivityTest : InjectableTest by InjectableTestImpl() {
 
     private fun Kodein.Builder.fakeLoadingDetail() {
         bind<UserInteractor>(overrides = true) with instance(mock<UserInteractor> {
-            on { get(any()) } doReturn Observable.empty()
+            on { get(any()) } doReturn Observable.just(TestUser)
         })
     }
 
diff --git a/app/src/androidTest/kotlin/com/hana053/micropost/testing/AppTestRunner.kt b/app/src/androidTest/kotlin/com/hana053/micropost/testing/AppTestRunner.kt
new file mode 100644
index 0000000..1b1635c
--- /dev/null
+++ b/app/src/androidTest/kotlin/com/hana053/micropost/testing/AppTestRunner.kt
@@ -0,0 +1,21 @@
+package com.hana053.micropost.testing
+
+import android.os.Bundle
+import android.support.test.InstrumentationRegistry
+import android.support.test.runner.AndroidJUnitRunner
+import com.linkedin.android.testbutler.TestButler
+
+
+class AppTestRunner : AndroidJUnitRunner() {
+
+    override fun onStart() {
+        TestButler.setup(InstrumentationRegistry.getTargetContext())
+        super.onStart()
+    }
+
+    override fun finish(resultCode: Int, results: Bundle) {
+        TestButler.teardown(InstrumentationRegistry.getTargetContext())
+        super.finish(resultCode, results)
+    }
+
+}
\ No newline at end of file
diff --git a/app/src/androidTest/kotlin/com/hana053/micropost/testing/EspressoHelpers.kt b/app/src/androidTest/kotlin/com/hana053/micropost/testing/EspressoHelpers.kt
index 6cdb1e2..7943acd 100644
--- a/app/src/androidTest/kotlin/com/hana053/micropost/testing/EspressoHelpers.kt
+++ b/app/src/androidTest/kotlin/com/hana053/micropost/testing/EspressoHelpers.kt
@@ -13,11 +13,11 @@ fun atPositionOnView(
     targetId: Int
 ) = object : BoundedMatcher<View, RecyclerView>(RecyclerView::class.java) {
 
-    override fun matchesSafely(recyclerView: RecyclerView): Boolean {
-        val viewHolder = recyclerView.findViewHolderForAdapterPosition(position)
-        val targetView = viewHolder.itemView.findViewById(targetId)
-        return matcher.matches(targetView)
-    }
+    override fun matchesSafely(recyclerView: RecyclerView) =
+        recyclerView.findViewHolderForAdapterPosition(position)
+            .itemView
+            .findViewById(targetId)
+            .let { matcher.matches(it) }
 
     override fun describeTo(description: Description?) {
         description?.appendText("has view id $matcher at position $position")
diff --git a/app/src/main/kotlin/com/hana053/micropost/BaseApplication.kt b/app/src/main/kotlin/com/hana053/micropost/BaseApplication.kt
index 75ca77e..a34f674 100644
--- a/app/src/main/kotlin/com/hana053/micropost/BaseApplication.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/BaseApplication.kt
@@ -49,8 +49,6 @@ abstract class BaseApplication : Application(), KodeinAware {
         Pair(RelatedUserListActivity::class.java, relatedUserListModule())
     )
 
-    fun getOverridingModule(clazz: Class<*>): Kodein.Module {
-        return overridingModules[clazz]!!
-    }
+    fun getOverridingModule(clazz: Class<*>) = overridingModules[clazz]!!
 
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/Extensions.kt b/app/src/main/kotlin/com/hana053/micropost/Extensions.kt
index 2b588fb..6b5de5d 100644
--- a/app/src/main/kotlin/com/hana053/micropost/Extensions.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/Extensions.kt
@@ -1,9 +1,6 @@
 package com.hana053.micropost
 
 import android.app.Activity
-import com.github.salomonbrys.kodein.Kodein
-
-fun Activity.getOverridingModule(clazz: Class<*>): Kodein.Module {
-    return (application as BaseApplication).getOverridingModule(clazz)
-}
 
+fun Activity.getOverridingModule() =
+    (application as BaseApplication).getOverridingModule(javaClass)
diff --git a/app/src/main/kotlin/com/hana053/micropost/domain/Avatar.kt b/app/src/main/kotlin/com/hana053/micropost/domain/Avatar.kt
index db9b681..5409fd5 100644
--- a/app/src/main/kotlin/com/hana053/micropost/domain/Avatar.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/domain/Avatar.kt
@@ -4,7 +4,5 @@ package com.hana053.micropost.domain
 interface Avatar {
     val avatarHash: String
 
-    fun avatarUrl(size: Int = 72): String {
-        return "https://secure.gravatar.com/avatar/$avatarHash?s=$size"
-    }
+    fun avatarUrl(size: Int = 72) = "https://secure.gravatar.com/avatar/$avatarHash?s=$size"
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/domain/RelatedUser.kt b/app/src/main/kotlin/com/hana053/micropost/domain/RelatedUser.kt
index b9d741f..a0057b0 100644
--- a/app/src/main/kotlin/com/hana053/micropost/domain/RelatedUser.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/domain/RelatedUser.kt
@@ -10,7 +10,7 @@ data class RelatedUser(
     val userStats: UserStats,
     val relationshipId: Long
 ) : Avatar {
-    fun toUser(): User {
-        return User(id, name, email, avatarHash, isFollowedByMe, userStats)
-    }
+
+    fun toUser() = User(id, name, email, avatarHash, isFollowedByMe, userStats)
+
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/domain/User.kt b/app/src/main/kotlin/com/hana053/micropost/domain/User.kt
index d19e7f0..3b37b74 100644
--- a/app/src/main/kotlin/com/hana053/micropost/domain/User.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/domain/User.kt
@@ -5,7 +5,6 @@ data class User(
     val name: String,
     val email: String?,
     override val avatarHash: String,
-    val isFollowedByMe: Boolean,
+    val isFollowedByMe: Boolean? = null,
     val userStats: UserStats
 ) : Avatar
-
diff --git a/app/src/main/kotlin/com/hana053/micropost/interactor/InteractorModule.kt b/app/src/main/kotlin/com/hana053/micropost/interactor/InteractorModule.kt
index 88f5769..6cd73e9 100644
--- a/app/src/main/kotlin/com/hana053/micropost/interactor/InteractorModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/interactor/InteractorModule.kt
@@ -17,19 +17,16 @@ fun interactorModule() = Kodein.Module {
     bind<OkHttpClient>() with singleton {
         val authTokenRepository = instance<AuthTokenRepository>()
 
-        OkHttpClient().newBuilder()
-            .addInterceptor { chain ->
-                val authToken = authTokenRepository.get()
-                val original = chain.request()
-                val builder = original.newBuilder()
-                if (authToken != null)
-                    builder.header("authorization", "Bearer " + authToken)
-                val request = builder
-                    .method(original.method(), original.body())
-                    .build()
-                chain.proceed(request)
-            }
-            .build()
+        OkHttpClient().newBuilder().addInterceptor { chain ->
+            val original = chain.request()
+            val modified = original.newBuilder().apply {
+                authTokenRepository.get()?.let {
+                    header("authorization", "Bearer $it")
+                }
+            }.method(original.method(), original.body()).build()
+
+            chain.proceed(modified)
+        }.build()
     }
 
     bind<Retrofit>() with singleton {
@@ -44,39 +41,33 @@ fun interactorModule() = Kodein.Module {
     }
 
     bind<LoginInteractor>() with singleton {
-        val retrofit = instance<Retrofit>()
-        retrofit.create(LoginInteractor::class.java)
+        instance<Retrofit>().create<LoginInteractor>()
     }
 
     bind<FeedInteractor>() with singleton {
-        val retrofit = instance<Retrofit>()
-        retrofit.create(FeedInteractor::class.java)
+        instance<Retrofit>().create<FeedInteractor>()
     }
 
     bind<UserInteractor>() with singleton {
-        val retrofit = instance<Retrofit>()
-        retrofit.create(UserInteractor::class.java)
+        instance<Retrofit>().create<UserInteractor>()
     }
 
     bind<RelationshipInteractor>() with singleton {
-        val retrofit = instance<Retrofit>()
-        retrofit.create(RelationshipInteractor::class.java)
+        instance<Retrofit>().create<RelationshipInteractor>()
     }
 
     bind<UserMicropostInteractor>() with singleton {
-        val retrofit = instance<Retrofit>()
-        retrofit.create(UserMicropostInteractor::class.java)
+        instance<Retrofit>().create<UserMicropostInteractor>()
     }
 
     bind<MicropostInteractor>() with singleton {
-        val retrofit = instance<Retrofit>()
-        retrofit.create(MicropostInteractor::class.java)
+        instance<Retrofit>().create<MicropostInteractor>()
     }
 
     bind<RelatedUserListInteractor>() with singleton {
-        val retrofit = instance<Retrofit>()
-        retrofit.create(RelatedUserListInteractor::class.java)
+        instance<Retrofit>().create<RelatedUserListInteractor>()
     }
-
 }
 
+inline fun <reified T : Any> Retrofit.create(): T = create(T::class.java)
+
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/Presenter.kt b/app/src/main/kotlin/com/hana053/micropost/pages/Presenter.kt
index ed76425..586d223 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/Presenter.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/Presenter.kt
@@ -15,21 +15,19 @@ interface Presenter<out T : ViewWrapper> {
     fun bind()
 
     fun <T> Observable<T>.withProgressDialog(): Observable<T> = Observable.using({
-        val progressBar = ProgressBar(view.content.context, null, android.R.attr.progressBarStyle)
-        progressBar.isIndeterminate = true
-        progressBar.visibility = View.VISIBLE
-
-        val rl = RelativeLayout(view.content.context)
-        rl.gravity = Gravity.CENTER
-        rl.addView(progressBar)
-
+        val progressBar = ProgressBar(view.content.context, null, android.R.attr.progressBarStyle).apply {
+            isIndeterminate = true
+            visibility = View.VISIBLE
+        }
+        val rl = RelativeLayout(view.content.context).apply {
+            gravity = Gravity.CENTER
+            addView(progressBar)
+        }
         val layoutParams = RelativeLayout.LayoutParams(
             RelativeLayout.LayoutParams.MATCH_PARENT,
             RelativeLayout.LayoutParams.MATCH_PARENT
         )
-
         view.content.addView(rl, layoutParams)
-
         progressBar
     }, { this }, {
         it.visibility = View.GONE
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/ViewWrapper.kt b/app/src/main/kotlin/com/hana053/micropost/pages/ViewWrapper.kt
index 33e4151..db1d08d 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/ViewWrapper.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/ViewWrapper.kt
@@ -1,8 +1,11 @@
 package com.hana053.micropost.pages
 
+import android.content.Context
 import android.view.ViewGroup
 
 
 interface ViewWrapper {
     val content: ViewGroup
+
+    fun context(): Context = content.context
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginActivity.kt b/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginActivity.kt
index 583946e..2482d98 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginActivity.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginActivity.kt
@@ -27,7 +27,6 @@ class LoginActivity : RxAppCompatActivity(), AppCompatActivityInjector {
         destroyInjector()
     }
 
-    override fun provideOverridingModule()
-        = getOverridingModule(LoginActivity::class.java)
+    override fun provideOverridingModule() = getOverridingModule()
 }
 
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginModule.kt
index f46f088..521013c 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginModule.kt
@@ -15,8 +15,7 @@ fun loginModule() = Kodein.Module {
     }
 
     bind<LoginView>() with autoScopedSingleton(androidActivityScope) {
-        val content = instance<Activity>().activity_login
-        LoginView(content)
+        instance<Activity>().activity_login.let(::LoginView)
     }
 
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginPresenter.kt b/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginPresenter.kt
index dadc621..c880d5b 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginPresenter.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginPresenter.kt
@@ -15,26 +15,28 @@ class LoginPresenter(
         val emailChanges = view.emailChanges.share()
         val passwordChanges = view.passwordChanges.share()
 
-        val credentials = Observable.combineLatest(emailChanges, passwordChanges, { email, password ->
-            Triple(email, password, email.isNotBlank() && password.isNotBlank())
-        })
+        val emailAndPassword = Observable.combineLatest(emailChanges, passwordChanges, ::EmailAndPassword)
 
-        credentials
+        emailAndPassword
             .bindToLifecycle()
-            .map { it.third }
+            .map { it.isValid() }
             .subscribe { view.loginEnabled.call(it) }
 
         view.loginClicks
             .bindToLifecycle()
-            .withLatestFrom(credentials, { click, credentials ->
-                credentials.first to credentials.second
+            .withLatestFrom(emailAndPassword, { click, emailAndPassword ->
+                emailAndPassword
             })
             .flatMap {
-                loginService.login(it.first, it.second)
+                loginService.login(it.email, it.password)
                     .withProgressDialog()
             }
             .subscribe { navigator.navigateToMain() }
     }
 
+    data class EmailAndPassword(val email: String, val password: String) {
+        fun isValid() = email.isNotBlank() && password.isNotBlank()
+    }
+
 }
 
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginView.kt b/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginView.kt
index 57230a7..cc16558 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/login/LoginView.kt
@@ -6,14 +6,19 @@ import com.jakewharton.rxbinding.view.clicks
 import com.jakewharton.rxbinding.view.enabled
 import com.jakewharton.rxbinding.widget.textChanges
 import kotlinx.android.synthetic.main.activity_login.view.*
+import rx.Observable
 
 class LoginView(override val content: ViewGroup) : ViewWrapper {
 
     // Events
-    val emailChanges = content.emailEditText.textChanges().map { it.toString() }!!
-    val passwordChanges = content.passwordEditText.textChanges().map { it.toString() }!!
-    val loginClicks = content.loginBtn.clicks()
+    val emailChanges: Observable<String> = content.et_email
+        .textChanges()
+        .map { it.toString() }
+    val passwordChanges: Observable<String> = content.et_password
+        .textChanges()
+        .map { it.toString() }
+    val loginClicks = content.btn_login.clicks()
 
     // Props
-    val loginEnabled = content.loginBtn.enabled()
+    val loginEnabled = content.btn_login.enabled()
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/main/MainActivity.kt b/app/src/main/kotlin/com/hana053/micropost/pages/main/MainActivity.kt
index fa60332..c97e31d 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/main/MainActivity.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/main/MainActivity.kt
@@ -62,7 +62,6 @@ class MainActivity : RxAppCompatActivity(), AppCompatActivityInjector {
         return super.onOptionsItemSelected(item)
     }
 
-    override fun provideOverridingModule()
-        = getOverridingModule(MainActivity::class.java)
+    override fun provideOverridingModule() = getOverridingModule()
 
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/main/MainModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/main/MainModule.kt
index 6b74867..d8966c6 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/main/MainModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/main/MainModule.kt
@@ -20,8 +20,8 @@ fun mainModule() = Kodein.Module {
     }
 
     bind<MainView>() with autoScopedSingleton(androidActivityScope) {
-        val content = instance<Activity>().activity_main
-        MainView(content, instance())
+        instance<Activity>().activity_main
+            .let { MainView(it, instance()) }
     }
 
     bind<MainService>() with autoScopedSingleton(androidActivityScope) {
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/main/MainPresenter.kt b/app/src/main/kotlin/com/hana053/micropost/pages/main/MainPresenter.kt
index f9973ee..ac14320 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/main/MainPresenter.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/main/MainPresenter.kt
@@ -26,7 +26,7 @@ class MainPresenter(
             .flatMap { mainService.loadNextFeed() }
             .subscribe { view.swipeRefreshing.call(false) }
 
-        view.scrolledToBottom
+        view.scrollsToBottom
             .bindToLifecycle()
             .flatMap {
                 mainService.loadPrevFeed()
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/main/MainView.kt b/app/src/main/kotlin/com/hana053/micropost/pages/main/MainView.kt
index e0f1495..509faff 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/main/MainView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/main/MainView.kt
@@ -17,23 +17,21 @@ class MainView(
     postListAdapter: PostListAdapter
 ) : ViewWrapper {
 
-    private val postRecyclerView = content.postRecyclerView
-    private val swipeRefreshLayout = content.swipeRefreshLayout
+    private val listPost = content.list_post
+    private val swipeRefresh = content.swipe_refresh
 
     // Events
-    val swipeRefreshes = swipeRefreshLayout.refreshes()
-    val scrolledToBottom: Observable<RecyclerViewScrollEvent> = postRecyclerView
-        .scrollEvents()
-        .filter { !postRecyclerView.canScrollVertically(1) }
-    val newMicropostClicks = content.newMicropostBtn.clicks()
+    val swipeRefreshes = swipeRefresh.refreshes()
+    val scrollsToBottom: Observable<RecyclerViewScrollEvent> = listPost.scrollEvents()
+        .filter { !listPost.canScrollVertically(1) }
+    val newMicropostClicks = content.btn_new_micropost.clicks()
 
     // Props
-    val swipeRefreshing = swipeRefreshLayout.refreshing()
+    val swipeRefreshing = swipeRefresh.refreshing()
 
     init {
-        val context = content.context
-        postRecyclerView.layoutManager = LinearLayoutManager(context)
-        postRecyclerView.adapter = postListAdapter
+        listPost.layoutManager = LinearLayoutManager(context())
+        listPost.adapter = postListAdapter
     }
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MIcropostNewModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MIcropostNewModule.kt
index b90542f..457d11d 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MIcropostNewModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MIcropostNewModule.kt
@@ -16,8 +16,7 @@ fun micropostNewModule() = Kodein.Module {
     }
 
     bind<MicropostNewView>() with autoScopedSingleton(androidActivityScope) {
-        val content = instance<Activity>().activity_micropost_new
-        MicropostNewView(content)
+        instance<Activity>().activity_micropost_new.let(::MicropostNewView)
     }
 
     bind<MicropostNewService>() with autoScopedSingleton(androidActivityScope) {
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewActivity.kt b/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewActivity.kt
index 73e28d3..b8613eb 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewActivity.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewActivity.kt
@@ -32,6 +32,5 @@ class MicropostNewActivity : RxAppCompatActivity(), AppCompatActivityInjector {
         destroyInjector()
     }
 
-    override fun provideOverridingModule()
-        = getOverridingModule(MicropostNewActivity::class.java)
+    override fun provideOverridingModule() = getOverridingModule()
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewView.kt b/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewView.kt
index 7f31b55..915dadb 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/micropostnew/MicropostNewView.kt
@@ -11,9 +11,9 @@ import kotlinx.android.synthetic.main.activity_micropost_new.view.*
 class MicropostNewView(override val content: ViewGroup) : ViewWrapper {
 
     // Events
-    val postTextChanges = content.postEditText.textChanges()
-    val postBtnClicks = content.postBtn.clicks()
+    val postTextChanges = content.et_post.textChanges()
+    val postBtnClicks = content.btn_post.clicks()
 
     // Props
-    val postBtnEnabled = content.postBtn.enabled()
+    val postBtnEnabled = content.btn_post.enabled()
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListActivity.kt b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListActivity.kt
index 41dc0ae..302122a 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListActivity.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListActivity.kt
@@ -57,7 +57,6 @@ class RelatedUserListActivity : RxAppCompatActivity(), AppCompatActivityInjector
         return super.onOptionsItemSelected(item)
     }
 
-    override fun provideOverridingModule()
-        = getOverridingModule(RelatedUserListActivity::class.java)
+    override fun provideOverridingModule() = getOverridingModule()
 
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListAdapter.kt b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListAdapter.kt
index b2bdf41..73e9474 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListAdapter.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListAdapter.kt
@@ -24,44 +24,42 @@ class RelatedUserListAdapter(
     val followBtnClicksSubject: PublishSubject<FollowBtnView> = PublishSubject.create()
     val avatarClicksSubject: PublishSubject<User> = PublishSubject.create()
 
-    override fun getItemCount(): Int {
-        return users.size
+    class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
+        val container: LinearLayout = view.container
+        val avatar: ImageView = view.img_avatar
+        val userName: TextView = view.tv_user_name
+        val followBtn: Button = view.btn_follow
     }
 
-    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
-        val v = LayoutInflater.from(parent.context)
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
+        LayoutInflater.from(parent.context)
             .inflate(R.layout.item_related_users, parent, false)
-        return ViewHolder(v)
-    }
+            .let(::ViewHolder)
 
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
         val item = users[position]
 
-        holder.userName.text = item.name
-        holder.container.tag = item
+        holder.apply {
+            container.tag = item
+            userName.text = item.name
 
-        AvatarView(holder.avatar).render(item.toUser())
-        holder.avatar.setOnClickListener {
-            avatarClicksSubject.onNext(item.toUser())
-        }
+            AvatarView(avatar).render(item.toUser())
+            avatar.setOnClickListener {
+                avatarClicksSubject.onNext(item.toUser())
+            }
 
-        val followBtnView = FollowBtnView(holder.followBtn)
-        followBtnView.render(item.toUser())
-        holder.followBtn.setOnClickListener {
-            followBtnClicksSubject.onNext(followBtnView)
+            FollowBtnView(followBtn).apply {
+                render(item.toUser())
+                followBtn.setOnClickListener {
+                    followBtnClicksSubject.onNext(this)
+                }
+            }
         }
     }
 
-    class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
-        val container: LinearLayout = view.container
-        val avatar: ImageView = view.avatar
-        val userName: TextView = view.userName
-        val followBtn: Button = view.followBtn
-    }
+    override fun getItemCount() = users.size
 
-    fun getLastItemId(): Long? {
-        return users.map { it.relationshipId }.lastOrNull()
-    }
+    fun getLastItemId() = users.map { it.relationshipId }.lastOrNull()
 
     fun addAll(location: Int, users: List<RelatedUser>): Boolean {
         if (this.users.addAll(location, users)) {
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListModule.kt
index 5726490..9d94d48 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListModule.kt
@@ -1,8 +1,11 @@
 package com.hana053.micropost.pages.relateduserlist
 
 import android.app.Activity
-import com.github.salomonbrys.kodein.*
+import com.github.salomonbrys.kodein.Kodein
 import com.github.salomonbrys.kodein.android.androidActivityScope
+import com.github.salomonbrys.kodein.autoScopedSingleton
+import com.github.salomonbrys.kodein.bind
+import com.github.salomonbrys.kodein.instance
 import com.hana053.micropost.pages.relateduserlist.RelatedUserListActivity.Companion.KEY_LIST_TYPE
 import com.hana053.micropost.pages.relateduserlist.RelatedUserListActivity.Companion.KEY_USER_ID
 import com.hana053.micropost.pages.relateduserlist.RelatedUserListActivity.ListType.FOLLOWER
@@ -20,8 +23,8 @@ fun relatedUserListModule() = Kodein.Module {
     }
 
     bind<RelatedUserListView>() with autoScopedSingleton(androidActivityScope) {
-        val content = instance<Activity>().activity_related_user_list
-        RelatedUserListView(content, instance())
+        instance<Activity>().activity_related_user_list
+            .let { RelatedUserListView(it, instance()) }
     }
 
     bind<RelatedUserListPresenter>() with autoScopedSingleton(androidActivityScope) {
@@ -35,15 +38,17 @@ fun relatedUserListModule() = Kodein.Module {
         }
     }
 
-    bind<Long>(KEY_USER_ID) with provider {
-        instance<Activity>().intent.extras.getLong(KEY_USER_ID)
+    bind<Long>(KEY_USER_ID) with autoScopedSingleton(androidActivityScope) {
+        extras().getLong(KEY_USER_ID)
     }
 
-    bind<RelatedUserListActivity.ListType>() with provider {
-        instance<Activity>().intent.extras.getSerializable(KEY_LIST_TYPE) as RelatedUserListActivity.ListType
+    bind<RelatedUserListActivity.ListType>() with autoScopedSingleton(androidActivityScope) {
+        extras().getSerializable(KEY_LIST_TYPE) as RelatedUserListActivity.ListType
     }
 
     import(followBtnModule())
 }
 
+private fun Kodein.extras() = instance<Activity>().intent.extras
+
 
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListPresenter.kt b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListPresenter.kt
index 1aeef8e..0f6de03 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListPresenter.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListPresenter.kt
@@ -21,7 +21,7 @@ class RelatedUserListPresenter(
             .withProgressDialog()
             .subscribe()
 
-        view.scrolledToBottom
+        view.scrollsToBottom
             .bindToLifecycle()
             .flatMap {
                 relatedUserListService.listUsers(userId)
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListView.kt b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListView.kt
index e3c873c..b230108 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/RelatedUserListView.kt
@@ -14,16 +14,15 @@ class RelatedUserListView(
     relatedUserListAdapter: RelatedUserListAdapter
 ) : ViewWrapper {
 
-    private val userRecyclerView = content.userRecyclerView
+    private val listUser = content.list_user
 
     // Events
-    val scrolledToBottom: Observable<RecyclerViewScrollEvent> = userRecyclerView.scrollEvents()
-        .filter { !userRecyclerView.canScrollVertically(1) }
+    val scrollsToBottom: Observable<RecyclerViewScrollEvent> = listUser.scrollEvents()
+        .filter { !listUser.canScrollVertically(1) }
 
     init {
-        val context = content.context
-        userRecyclerView.layoutManager = LinearLayoutManager(context)
-        userRecyclerView.adapter = relatedUserListAdapter
+        listUser.layoutManager = LinearLayoutManager(context())
+        listUser.adapter = relatedUserListAdapter
     }
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/followerlist/FollowerListService.kt b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/followerlist/FollowerListService.kt
index e82810f..d9f93a4 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/followerlist/FollowerListService.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/followerlist/FollowerListService.kt
@@ -19,11 +19,7 @@ class FollowerListService(
     context: Context
 ) : RelatedUserListService {
 
-    private val context: Context
-
-    init {
-        this.context = context.applicationContext
-    }
+    private val context = context.applicationContext
 
     override fun listUsers(userId: Long): Observable<List<RelatedUser>> {
         val maxId = adapter.getLastItemId()
@@ -37,7 +33,5 @@ class FollowerListService(
             .onErrorResumeNext { Observable.empty() }
     }
 
-    override fun title(): String {
-        return context.getString(R.string.Followers)
-    }
+    override fun title(): String = context.getString(R.string.Followers)
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/followinglist/FollowingListService.kt b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/followinglist/FollowingListService.kt
index 92f6a33..62af020 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/followinglist/FollowingListService.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/relateduserlist/followinglist/FollowingListService.kt
@@ -19,11 +19,7 @@ class FollowingListService(
     context: Context
 ) : RelatedUserListService {
 
-    private val context: Context
-
-    init {
-        this.context = context.applicationContext
-    }
+    private val context = context.applicationContext
 
     override fun listUsers(userId: Long): Observable<List<RelatedUser>> {
         val maxId = adapter.getLastItemId()
@@ -37,7 +33,5 @@ class FollowingListService(
             .onErrorResumeNext { Observable.empty() }
     }
 
-    override fun title(): String {
-        return context.getString(R.string.Followings)
-    }
+    override fun title(): String = context.getString(R.string.Followings)
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupActivity.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupActivity.kt
index 92d9226..f0ee92e 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupActivity.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupActivity.kt
@@ -39,7 +39,6 @@ class SignupActivity : RxAppCompatActivity(), AppCompatActivityInjector {
         signupNavigator.navigateToPrev()
     }
 
-    override fun provideOverridingModule()
-        = getOverridingModule(SignupActivity::class.java)
+    override fun provideOverridingModule() = getOverridingModule()
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupNavigatorImpl.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupNavigatorImpl.kt
index d62c340..52c7112 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupNavigatorImpl.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupNavigatorImpl.kt
@@ -27,12 +27,12 @@ class SignupNavigatorImpl(
     }
 
     override fun navigateToPrev() {
-        val backStackCnt = activity.supportFragmentManager.backStackEntryCount
-        if (backStackCnt == 0) {
-            activity.finish()
-            return
+        activity.supportFragmentManager.backStackEntryCount.let {
+            when (it) {
+                0 -> activity.finish()
+                else -> activity.supportFragmentManager.popBackStack()
+            }
         }
-        activity.supportFragmentManager.popBackStack()
     }
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupServiceImpl.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupServiceImpl.kt
index e8c921d..2c2c795 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupServiceImpl.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupServiceImpl.kt
@@ -5,7 +5,7 @@ import android.widget.Toast
 import com.hana053.micropost.interactor.UserInteractor
 import com.hana053.micropost.service.HttpErrorHandler
 import com.hana053.micropost.service.LoginService
-import retrofit2.adapter.rxjava.HttpException
+import retrofit2.HttpException
 import rx.Observable
 import rx.android.schedulers.AndroidSchedulers
 import rx.schedulers.Schedulers
@@ -21,26 +21,24 @@ class SignupServiceImpl(
 
     private val context = context.applicationContext
 
-    override fun signup(request: UserInteractor.SignupRequest): Observable<Void> {
-        return userInteractor.create(request)
+    override fun signup(request: UserInteractor.SignupRequest): Observable<Void> =
+        userInteractor.create(request)
             .subscribeOn(Schedulers.newThread())
             .observeOn(AndroidSchedulers.mainThread())
-            .doOnError { err ->
-                if (isEmailAlreadyTaken(err)) {
-                    Toast.makeText(context, "This email is already taken.", Toast.LENGTH_LONG).show()
-                    signupNavigator.navigateToPrev()
-                } else {
-                    httpErrorHandler.handleError(err)
+            .doOnError {
+                when {
+                    isEmailAlreadyTaken(it) -> {
+                        Toast.makeText(context, "This email is already taken.", Toast.LENGTH_LONG).show()
+                        signupNavigator.navigateToPrev()
+                    }
+                    else -> httpErrorHandler.handleError(it)
                 }
             }
             .onErrorResumeNext { Observable.empty() }
             .flatMap {
                 loginService.login(request.email, request.password)
             }
-    }
 
-    private fun isEmailAlreadyTaken(e: Throwable): Boolean {
-        return e is HttpException && e.code() == 400
-    }
+    private fun isEmailAlreadyTaken(e: Throwable) = e is HttpException && e.code() == 400
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupState.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupState.kt
index 18bf965..43f23ea 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupState.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/SignupState.kt
@@ -8,7 +8,7 @@ data class SignupState(
     var email: String = "",
     var password: String = ""
 ) {
-    fun toSignupRequest(): UserInteractor.SignupRequest {
-        return UserInteractor.SignupRequest(fullName, email, password)
-    }
+
+    fun toSignupRequest() = UserInteractor.SignupRequest(fullName, email, password)
+
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailFragment.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailFragment.kt
index 85922e4..16cfcd7 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailFragment.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailFragment.kt
@@ -17,9 +17,8 @@ class SignupEmailFragment : RxFragment(), SupportFragmentInjector {
 
     private val presenter: SignupEmailPresenter by instance()
 
-    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
-        return inflater.inflate(R.layout.fragment_signup_email, container, false)
-    }
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? =
+        inflater.inflate(R.layout.fragment_signup_email, container, false)
 
     override fun onActivityCreated(savedInstanceState: Bundle?) {
         super.onActivityCreated(savedInstanceState)
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailPresenter.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailPresenter.kt
index fe95a8d..cb8c009 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailPresenter.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailPresenter.kt
@@ -33,9 +33,9 @@ class SignupEmailPresenter(
             }
     }
 
-    private fun isFormValid(email: CharSequence): Boolean {
-        val emailPattern = "^[^0-9][a-zA-Z0-9_]+([.][a-zA-Z0-9_]+)*@\\[?([\\d\\w\\.-]+)]?$"
-        return email.matches(emailPattern.toRegex())
-    }
+    private fun isFormValid(email: CharSequence) =
+        "^[^0-9][a-zA-Z0-9_]+([.][a-zA-Z0-9_]+)*@\\[?([\\d\\w\\.-]+)]?$"
+            .let(String::toRegex)
+            .let { email.matches(it) }
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailView.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailView.kt
index c28b5ad..5a9b0d8 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupEmailView.kt
@@ -12,11 +12,11 @@ import kotlinx.android.synthetic.main.fragment_signup_email.view.*
 class SignupEmailView(override val content: ViewGroup) : ViewWrapper {
 
     // Events
-    val emailChanges = content.email.textChanges()
-    val nextBtnClicks = content.emailNextBtn.clicks()
+    val emailChanges = content.et_email.textChanges()
+    val nextBtnClicks = content.btn_next.clicks()
 
     // Props
-    val nextBtnEnabled = content.emailNextBtn.enabled()
-    val emailInvalidVisibility = content.emailInvalid.visibility()
+    val nextBtnEnabled = content.btn_next.enabled()
+    val emailInvalidVisibility = content.tv_email_invalid.visibility()
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupFullNameModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupFullNameModule.kt
index 931943d..3a0e289 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupFullNameModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/email/SignupFullNameModule.kt
@@ -16,8 +16,7 @@ fun signupEmailModule() = Kodein.Module {
     }
 
     bind<SignupEmailView>() with autoScopedSingleton(androidActivityScope) {
-        val content = instance<Activity>().fragment_signup_email
-        SignupEmailView(content)
+        instance<Activity>().fragment_signup_email.let(::SignupEmailView)
     }
 
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameFragment.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameFragment.kt
index d3fc7b2..c4d03ef 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameFragment.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameFragment.kt
@@ -17,9 +17,8 @@ class SignupFullNameFragment : RxFragment(), SupportFragmentInjector {
 
     private val presenter: SignupFullNamePresenter by instance()
 
-    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
-        return inflater.inflate(R.layout.fragment_signup_full_name, container, false)
-    }
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? =
+        inflater.inflate(R.layout.fragment_signup_full_name, container, false)
 
     override fun onActivityCreated(savedInstanceState: Bundle?) {
         super.onActivityCreated(savedInstanceState)
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameModule.kt
index a28ab90..d52bc6d 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameModule.kt
@@ -16,8 +16,7 @@ fun signupFullNameModule() = Kodein.Module {
     }
 
     bind<SignupFullNameView>() with autoScopedSingleton(androidActivityScope) {
-        val content = instance<Activity>().fragment_signup_full_name
-        SignupFullNameView(content)
+        instance<Activity>().fragment_signup_full_name.let(::SignupFullNameView)
     }
 
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNamePresenter.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNamePresenter.kt
index bf01de0..3d6e615 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNamePresenter.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNamePresenter.kt
@@ -33,8 +33,6 @@ class SignupFullNamePresenter(
             }
     }
 
-    private fun isFormValid(fullName: CharSequence): Boolean {
-        return fullName.length >= 4
-    }
+    private fun isFormValid(fullName: CharSequence) = fullName.length >= 4
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameView.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameView.kt
index 58e660e..7e48508 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/fullname/SignupFullNameView.kt
@@ -12,11 +12,11 @@ import kotlinx.android.synthetic.main.fragment_signup_full_name.view.*
 class SignupFullNameView(override val content: ViewGroup) : ViewWrapper {
 
     // Events
-    val fullNameChanges = content.fullName.textChanges()
-    val nextBtnClicks = content.fullNameNextBtn.clicks()
+    val fullNameChanges = content.et_full_name.textChanges()
+    val nextBtnClicks = content.btn_next.clicks()
 
     // Props
-    val nextBtnEnabled = content.fullNameNextBtn.enabled()
-    val fullNameInvalidVisibility = content.fullNameInvalid.visibility()
+    val nextBtnEnabled = content.btn_next.enabled()
+    val fullNameInvalidVisibility = content.tv_full_name_invalid.visibility()
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordFragment.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordFragment.kt
index 6bf0ee3..85b1c15 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordFragment.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordFragment.kt
@@ -17,9 +17,8 @@ class SignupPasswordFragment : RxFragment(), SupportFragmentInjector {
 
     private val presenter: SignupPasswordPresenter by instance()
 
-    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
-        return inflater.inflate(R.layout.fragment_signup_password, container, false)
-    }
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? =
+        inflater.inflate(R.layout.fragment_signup_password, container, false)
 
     override fun onActivityCreated(savedInstanceState: Bundle?) {
         super.onActivityCreated(savedInstanceState)
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordModule.kt
index 4b03631..9e94b1b 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordModule.kt
@@ -16,8 +16,7 @@ fun signupPasswordModule() = Kodein.Module {
     }
 
     bind<SignupPasswordView>() with autoScopedSingleton(androidActivityScope) {
-        val content = instance<Activity>().fragment_signup_password
-        SignupPasswordView(content)
+        instance<Activity>().fragment_signup_password.let(::SignupPasswordView)
     }
 
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordPresenter.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordPresenter.kt
index fa97496..e86a4ec 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordPresenter.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordPresenter.kt
@@ -41,8 +41,6 @@ class SignupPasswordPresenter(
             .subscribe { navigator.navigateToMain() }
     }
 
-    private fun isFormValid(password: CharSequence): Boolean {
-        return password.length >= 8
-    }
+    private fun isFormValid(password: CharSequence): Boolean = password.length >= 8
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordView.kt b/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordView.kt
index ceb1b9c..a555424 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/signup/password/SignupPasswordView.kt
@@ -12,10 +12,10 @@ import kotlinx.android.synthetic.main.fragment_signup_password.view.*
 class SignupPasswordView(override val content: ViewGroup) : ViewWrapper {
 
     // Events
-    val passwordChanges = content.password.textChanges()
-    val nextBtnClicks = content.passwordNextBtn.clicks()
+    val passwordChanges = content.et_password.textChanges()
+    val nextBtnClicks = content.btn_next.clicks()
 
     // Props
-    val nextBtnEnabled = content.passwordNextBtn.enabled()
-    val passwordInvalidVisibility = content.passwordInvalid.visibility()
+    val nextBtnEnabled = content.btn_next.enabled()
+    val passwordInvalidVisibility = content.tv_password_invalid.visibility()
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/top/TopActivity.kt b/app/src/main/kotlin/com/hana053/micropost/pages/top/TopActivity.kt
index 6c4000c..aa0b0a8 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/top/TopActivity.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/top/TopActivity.kt
@@ -28,8 +28,7 @@ class TopActivity : RxAppCompatActivity(), AppCompatActivityInjector {
         destroyInjector()
     }
 
-    override fun provideOverridingModule()
-        = getOverridingModule(TopActivity::class.java)
+    override fun provideOverridingModule() = getOverridingModule()
 
 }
 
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/top/TopModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/top/TopModule.kt
index c221cad..451cd0a 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/top/TopModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/top/TopModule.kt
@@ -15,8 +15,7 @@ fun topModule() = Kodein.Module {
     }
 
     bind<TopView>() with autoScopedSingleton(androidActivityScope) {
-        val content = instance<Activity>().activity_top
-        TopView(content)
+        instance<Activity>().activity_top.let(::TopView)
     }
 
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/top/TopView.kt b/app/src/main/kotlin/com/hana053/micropost/pages/top/TopView.kt
index 76594a9..cfbb5ad 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/top/TopView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/top/TopView.kt
@@ -7,6 +7,6 @@ import kotlinx.android.synthetic.main.activity_top.view.*
 
 class TopView(override val content: ViewGroup) : ViewWrapper {
 
-    val signupClicks = content.signupBtn.clicks()
-    val loginClicks = content.loginBtn.clicks()
+    val signupClicks = content.btn_signup.clicks()
+    val loginClicks = content.btn_login.clicks()
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/UserShowActivity.kt b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/UserShowActivity.kt
index 5524051..afe5a64 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/UserShowActivity.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/UserShowActivity.kt
@@ -53,7 +53,6 @@ class UserShowActivity : RxAppCompatActivity(), AppCompatActivityInjector {
         return super.onOptionsItemSelected(item)
     }
 
-    override fun provideOverridingModule()
-        = getOverridingModule(UserShowActivity::class.java)
+    override fun provideOverridingModule() = getOverridingModule()
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/UserShowModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/UserShowModule.kt
index baa7cb3..d9ab323 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/UserShowModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/UserShowModule.kt
@@ -2,9 +2,10 @@ package com.hana053.micropost.pages.usershow
 
 import android.app.Activity
 import com.github.salomonbrys.kodein.Kodein
+import com.github.salomonbrys.kodein.android.androidActivityScope
+import com.github.salomonbrys.kodein.autoScopedSingleton
 import com.github.salomonbrys.kodein.bind
 import com.github.salomonbrys.kodein.instance
-import com.github.salomonbrys.kodein.provider
 import com.hana053.micropost.pages.usershow.UserShowActivity.Companion.KEY_USER_ID
 import com.hana053.micropost.pages.usershow.detail.userShowDetailModule
 import com.hana053.micropost.pages.usershow.posts.userShowPostsModule
@@ -12,7 +13,7 @@ import com.hana053.micropost.shared.followbtn.followBtnModule
 
 fun userShowModule() = Kodein.Module {
 
-    bind<Long>(KEY_USER_ID) with provider {
+    bind<Long>(KEY_USER_ID) with autoScopedSingleton(androidActivityScope) {
         instance<Activity>().intent.extras.getLong(KEY_USER_ID)
     }
 
@@ -22,4 +23,3 @@ fun userShowModule() = Kodein.Module {
 
 }
 
-
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailModule.kt
index 4ccf54d..30d7f7c 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailModule.kt
@@ -16,8 +16,7 @@ fun userShowDetailModule() = Kodein.Module {
     }
 
     bind<UserShowDetailView>() with autoScopedSingleton(androidActivityScope) {
-        val content = instance<Activity>()._user_detail
-        UserShowDetailView(content)
+        instance<Activity>()._user_detail.let(::UserShowDetailView)
     }
 
     bind<UserShowDetailPresenter>() with autoScopedSingleton(androidActivityScope) {
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailService.kt b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailService.kt
index 3c89525..8e34ab7 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailService.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailService.kt
@@ -13,12 +13,11 @@ class UserShowDetailService(
     private val httpErrorHandler: HttpErrorHandler
 ) {
 
-    fun getUser(userId: Long): Observable<User> {
-        return userInteractor.get(userId)
+    fun getUser(userId: Long): Observable<User> =
+        userInteractor.get(userId)
             .subscribeOn(Schedulers.newThread())
             .observeOn(AndroidSchedulers.mainThread())
             .doOnError { httpErrorHandler.handleError(it) }
             .onErrorResumeNext { Observable.empty() }
-    }
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailView.kt b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailView.kt
index cdbcb00..dd0fb43 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailView.kt
@@ -2,6 +2,7 @@ package com.hana053.micropost.pages.usershow.detail
 
 import android.annotation.SuppressLint
 import android.view.ViewGroup
+import com.hana053.micropost.R
 import com.hana053.micropost.domain.User
 import com.hana053.micropost.pages.ViewWrapper
 import com.hana053.micropost.shared.avatar.AvatarView
@@ -13,15 +14,13 @@ class UserShowDetailView(
     override val content: ViewGroup
 ) : ViewWrapper {
 
-    private val userName = content.userName
-    private val followerCnt = content.followerCnt
-    private val followingCnt = content.followingCnt
-    private val followers = content.followers
-    private val followings = content.followings
+    private val userName = content.tv_user_name
+    private val followers = content.tv_followers
+    private val followings = content.tv_followings
 
     // Sub View
-    private val followBtnView = FollowBtnView(content.followBtn)
-    private val avatarView = AvatarView(content.avatar)
+    private val followBtnView = FollowBtnView(content.btn_follow)
+    private val avatarView = AvatarView(content.img_avatar)
 
     // Events
     val followersClicks = followers.clicks()
@@ -33,8 +32,8 @@ class UserShowDetailView(
         followBtnView.render(user)
         avatarView.render(user)
         userName.text = user.name
-        followingCnt.text = "${user.userStats.followingCnt} "
-        followerCnt.text = "${user.userStats.followerCnt} "
+        followers.text = "${user.userStats.followerCnt} ${context().getString(R.string.followers)}"
+        followings.text = "${user.userStats.followingCnt} ${context().getString(R.string.followings)}"
     }
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsModule.kt b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsModule.kt
index 0ecc1f7..f0d74d8 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsModule.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsModule.kt
@@ -21,8 +21,8 @@ fun userShowPostsModule() = Kodein.Module {
     }
 
     bind<UserShowPostsView>() with autoScopedSingleton(androidActivityScope) {
-        val content = instance<Activity>()._user_posts
-        UserShowPostsView(content, instance())
+        instance<Activity>()._user_posts
+            .let { UserShowPostsView(it, instance()) }
     }
 
     bind<UserShowPostsPresenter>() with autoScopedSingleton(androidActivityScope) {
diff --git a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsView.kt b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsView.kt
index ca4deb7..0ed32d2 100644
--- a/app/src/main/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsView.kt
@@ -12,12 +12,13 @@ class UserShowPostsView(
     postListAdapter: PostListAdapter
 ) : ViewWrapper {
 
-    private val postRecyclerView = content.postRecyclerView
+    private val listPost = content.list_post
 
     init {
-        val context = content.context
-        postRecyclerView.layoutManager = LinearLayoutManager(context)
-        postRecyclerView.adapter = postListAdapter
-        postRecyclerView.isNestedScrollingEnabled = false
+        with(listPost) {
+            layoutManager = LinearLayoutManager(context())
+            adapter = postListAdapter
+            isNestedScrollingEnabled = false
+        }
     }
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/repository/AuthTokenRepositoryImpl.kt b/app/src/main/kotlin/com/hana053/micropost/repository/AuthTokenRepositoryImpl.kt
index 5034246..bb5db7a 100644
--- a/app/src/main/kotlin/com/hana053/micropost/repository/AuthTokenRepositoryImpl.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/repository/AuthTokenRepositoryImpl.kt
@@ -8,20 +8,17 @@ class AuthTokenRepositoryImpl(
 
     private val AUTH_TOKEN = "AUTH_TOKEN"
 
-    override fun get(): String? {
-        return sharedPreferences.getString(AUTH_TOKEN, null)
-    }
+    override fun get(): String? =
+        sharedPreferences.getString(AUTH_TOKEN, null)
 
-    override fun set(authToken: String) {
+    override fun set(authToken: String) =
         sharedPreferences.edit()
             .putString(AUTH_TOKEN, authToken)
             .apply()
-    }
 
-    override fun clear() {
+    override fun clear() =
         sharedPreferences.edit()
             .putString(AUTH_TOKEN, null)
             .apply()
-    }
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/service/AuthServiceImpl.kt b/app/src/main/kotlin/com/hana053/micropost/service/AuthServiceImpl.kt
index fe90f2a..8d112ad 100644
--- a/app/src/main/kotlin/com/hana053/micropost/service/AuthServiceImpl.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/service/AuthServiceImpl.kt
@@ -3,8 +3,6 @@ package com.hana053.micropost.service
 import com.hana053.micropost.domain.User
 import com.hana053.micropost.repository.AuthTokenRepository
 import com.nimbusds.jose.JWSObject
-import java.lang.Long
-import java.text.ParseException
 
 
 class AuthServiceImpl(
@@ -14,13 +12,11 @@ class AuthServiceImpl(
 
     override fun isMyself(user: User): Boolean {
         val authToken = authTokenRepository.get() ?: return false
-        try {
-            val jwsObject = JWSObject.parse(authToken)
-            val sub = jwsObject.payload.toJSONObject()["sub"].toString()
-            return user.id == Long.valueOf(sub)
-        } catch (e: ParseException) {
-            throw RuntimeException(e)
-        }
+        return user.id == JWSObject.parse(authToken)
+            .payload
+            .toJSONObject()["sub"]
+            .toString()
+            .toLong()
 
     }
 
diff --git a/app/src/main/kotlin/com/hana053/micropost/service/HttpErrorHandler.java b/app/src/main/kotlin/com/hana053/micropost/service/HttpErrorHandler.java
deleted file mode 100644
index c37d67a..0000000
--- a/app/src/main/kotlin/com/hana053/micropost/service/HttpErrorHandler.java
+++ /dev/null
@@ -1,7 +0,0 @@
-package com.hana053.micropost.service;
-
-public interface HttpErrorHandler {
-
-    void handleError(Throwable throwable);
-
-}
diff --git a/app/src/main/kotlin/com/hana053/micropost/service/HttpErrorHandler.kt b/app/src/main/kotlin/com/hana053/micropost/service/HttpErrorHandler.kt
new file mode 100644
index 0000000..715fd03
--- /dev/null
+++ b/app/src/main/kotlin/com/hana053/micropost/service/HttpErrorHandler.kt
@@ -0,0 +1,7 @@
+package com.hana053.micropost.service
+
+interface HttpErrorHandler {
+
+    fun handleError(throwable: Throwable)
+
+}
diff --git a/app/src/main/kotlin/com/hana053/micropost/service/HttpErrorHandlerImpl.kt b/app/src/main/kotlin/com/hana053/micropost/service/HttpErrorHandlerImpl.kt
index 4a95357..461c3b9 100644
--- a/app/src/main/kotlin/com/hana053/micropost/service/HttpErrorHandlerImpl.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/service/HttpErrorHandlerImpl.kt
@@ -2,7 +2,7 @@ package com.hana053.micropost.service
 
 import android.content.Context
 import android.widget.Toast
-import retrofit2.adapter.rxjava.HttpException
+import retrofit2.HttpException
 import timber.log.Timber
 import java.net.ConnectException
 import java.net.SocketTimeoutException
@@ -15,23 +15,27 @@ internal class HttpErrorHandlerImpl(
     private val context: Context = context.applicationContext
 
     override fun handleError(throwable: Throwable) {
-        try {
-            throw throwable
-        } catch (e: SocketTimeoutException) {
-            Toast.makeText(context, "Connection timed out.", Toast.LENGTH_LONG).show()
-        } catch (e: ConnectException) {
-            Toast.makeText(context, "Cannot connect to server.", Toast.LENGTH_LONG).show()
-        } catch (e: HttpException) {
-            if (e.code() == 401) {
-                Toast.makeText(context, "Please sign in.", Toast.LENGTH_LONG).show()
-                authService.logout()
-            } else if (e.code() >= 500) {
-                Toast.makeText(context, "Something bad happened.", Toast.LENGTH_LONG).show()
+        when (throwable) {
+            is SocketTimeoutException -> showToast("Connection timed out.")
+            is ConnectException -> showToast("Cannot connect to server.")
+            is HttpException -> {
+                when {
+                    (throwable.code() == 401) -> {
+                        showToast("Please sign in.")
+                        authService.logout()
+                    }
+                    (throwable.code() >= 500) -> showToast("Something bad happened.")
+                }
+            }
+            is Throwable -> {
+                Timber.e(throwable, "handleHttpError: ${throwable.message}")
+                showToast("Something bad happened.")
             }
-        } catch (e: Throwable) {
-            Timber.e(e, "handleHttpError: ${e.message}")
-            Toast.makeText(context, "Something bad happened.", Toast.LENGTH_LONG).show()
         }
     }
 
+    private fun showToast(msg: String) {
+        Toast.makeText(context, msg, Toast.LENGTH_LONG).show()
+    }
+
 }
diff --git a/app/src/main/kotlin/com/hana053/micropost/service/LoginServiceImpl.kt b/app/src/main/kotlin/com/hana053/micropost/service/LoginServiceImpl.kt
index 432514c..db0baf5 100644
--- a/app/src/main/kotlin/com/hana053/micropost/service/LoginServiceImpl.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/service/LoginServiceImpl.kt
@@ -4,7 +4,7 @@ import android.content.Context
 import android.widget.Toast
 import com.hana053.micropost.interactor.LoginInteractor
 import com.hana053.micropost.repository.AuthTokenRepository
-import retrofit2.adapter.rxjava.HttpException
+import retrofit2.HttpException
 import rx.Observable
 import rx.android.schedulers.AndroidSchedulers
 import rx.schedulers.Schedulers
@@ -25,11 +25,11 @@ class LoginServiceImpl(
             .subscribeOn(Schedulers.newThread())
             .observeOn(AndroidSchedulers.mainThread())
             .doOnNext { authTokenRepository.set(it.token) }
-            .doOnError { err ->
-                if (err is HttpException && err.code() == 401) {
-                    Toast.makeText(context, "Email or Password is wrong.", Toast.LENGTH_LONG).show()
-                } else {
-                    httpErrorHandler.handleError(err)
+            .doOnError {
+                when {
+                    it is HttpException && it.code() == 401 ->
+                        Toast.makeText(context, "Email or Password is wrong.", Toast.LENGTH_LONG).show()
+                    else -> httpErrorHandler.handleError(it)
                 }
             }
             .onErrorResumeNext(Observable.empty())
diff --git a/app/src/main/kotlin/com/hana053/micropost/shared/avatar/AvatarView.kt b/app/src/main/kotlin/com/hana053/micropost/shared/avatar/AvatarView.kt
index 98141b2..b1bf20c 100644
--- a/app/src/main/kotlin/com/hana053/micropost/shared/avatar/AvatarView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/shared/avatar/AvatarView.kt
@@ -6,12 +6,14 @@ import com.squareup.picasso.Picasso
 
 
 class AvatarView(
-    private val content: ImageView
+    private val content: ImageView,
+    private val size: Int = 96
+
 ) {
 
     fun render(user: User) {
         Picasso.with(content.context)
-            .load(user.avatarUrl(96))
+            .load(user.avatarUrl(size))
             .into(content)
     }
 
diff --git a/app/src/main/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnService.kt b/app/src/main/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnService.kt
index b5f4b4d..cbecd92 100644
--- a/app/src/main/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnService.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnService.kt
@@ -16,32 +16,27 @@ class FollowBtnService(
     fun handleFollowBtnClicks(view: FollowBtnView): Observable<User> {
         val obs = if (view.isFollowState()) follow(view) else unfollow(view)
         return obs.withBtnDisabled(view.enabled)
+            .doOnError { httpErrorHandler.handleError(it) }
+            .onErrorResumeNext { Observable.empty() }
             .map { view.user }
     }
 
-    private fun follow(view: FollowBtnView): Observable<Void> {
-        return relationshipInteractor.follow(view.user.id)
+    private fun follow(view: FollowBtnView) =
+        relationshipInteractor.follow(view.user.id)
             .subscribeOn(Schedulers.newThread())
             .observeOn(AndroidSchedulers.mainThread())
             .doOnNext { view.toUnfollow() }
-            .doOnError { httpErrorHandler.handleError(it) }
-            .onErrorResumeNext { Observable.empty() }
-    }
 
-    private fun unfollow(view: FollowBtnView): Observable<Void> {
-        return relationshipInteractor.unfollow(view.user.id)
+    private fun unfollow(view: FollowBtnView) =
+        relationshipInteractor.unfollow(view.user.id)
             .subscribeOn(Schedulers.newThread())
             .observeOn(AndroidSchedulers.mainThread())
             .doOnNext { view.toFollow() }
-            .doOnError { httpErrorHandler.handleError(it) }
-            .onErrorResumeNext { Observable.empty() }
-    }
 
-    private fun <T> Observable<T>.withBtnDisabled(enabled: Action1<in Boolean>): Observable<T> {
-        return Observable.using({
+    private fun <T> Observable<T>.withBtnDisabled(enabled: Action1<in Boolean>) =
+        Observable.using({
             enabled.call(false)
         }, { this }, {
             enabled.call(true)
         })
-    }
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnView.kt b/app/src/main/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnView.kt
index 6949465..0e1a64f 100644
--- a/app/src/main/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnView.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnView.kt
@@ -30,13 +30,11 @@ class FollowBtnView(
         val authService = button.context.appKodein().instance<AuthService>()
 
         button.visibility().call(!authService.isMyself(user))
-        if (user.isFollowedByMe) toUnfollow() else toFollow()
+        user.isFollowedByMe?.let { if(it) toUnfollow() else toFollow()}
         this._user = user
     }
 
-    fun clicks(): Observable<FollowBtnView> {
-        return button.clicks().map { this }
-    }
+    fun clicks(): Observable<FollowBtnView> = button.clicks().map { this }
 
     fun toFollow() {
         button.text = FOLLOW
@@ -46,8 +44,6 @@ class FollowBtnView(
         button.text = UNFOLLOW
     }
 
-    fun isFollowState(): Boolean {
-        return button.text == FOLLOW
-    }
+    fun isFollowState() = button.text == FOLLOW
 
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/com/hana053/micropost/shared/posts/PostListAdapter.kt b/app/src/main/kotlin/com/hana053/micropost/shared/posts/PostListAdapter.kt
index 1bc660a..87f2957 100644
--- a/app/src/main/kotlin/com/hana053/micropost/shared/posts/PostListAdapter.kt
+++ b/app/src/main/kotlin/com/hana053/micropost/shared/posts/PostListAdapter.kt
@@ -22,46 +22,41 @@ class PostListAdapter(
 
     val avatarClicksSubject: PublishSubject<User> = PublishSubject.create<User>()
 
-    override fun getItemCount(): Int {
-        return posts.size
+    class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
+        val container: LinearLayout = view.container
+        val avatar: ImageView = view.img_avatar
+        val userName: TextView = view.tv_post_user_name
+        val createdAt: RelativeTimeTextView = view.tv_post_created_at
+        val content: TextView = view.tv_post_content
     }
 
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
+        LayoutInflater.from(parent.context)
+            .inflate(R.layout.item_posts, parent, false)
+            .let(::ViewHolder)
+
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
         val item = posts[position]
-        holder.userName.text = item.user.name
-        holder.createdAt.setReferenceTime(item.createdAt)
-        holder.content.text = item.content
-        holder.container.tag = item
 
-        AvatarView(holder.avatar).render(item.user)
-        holder.avatar.setOnClickListener {
-            avatarClicksSubject.onNext(item.user)
+        holder.apply {
+            container.tag = item
+            userName.text = item.user.name
+            createdAt.setReferenceTime(item.createdAt)
+            content.text = item.content
+            AvatarView(avatar).render(item.user)
+            avatar.setOnClickListener {
+                avatarClicksSubject.onNext(item.user)
+            }
         }
     }
 
-    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
-        val v = LayoutInflater.from(parent.context)
-            .inflate(R.layout.item_posts, parent, false)
-        return ViewHolder(v)
-    }
-
-    class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
-        val container: LinearLayout = view.container
-        val avatar: ImageView = view.avatar
-        val userName: TextView = view.userName
-        val createdAt: RelativeTimeTextView = view.createdAt
-        val content: TextView = view.content
-    }
+    override fun getItemCount(): Int = posts.size
 
-    fun getFirstItemId(): Long? {
-        return posts.map { it.id }.firstOrNull()
-    }
+    fun getFirstItemId(): Long? = posts.map { it.id }.firstOrNull()
 
-    fun getLastItemId(): Long? {
-        return posts.map { it.id }.lastOrNull()
-    }
+    fun getLastItemId(): Long? = posts.map { it.id }.lastOrNull()
 
-    fun addAll(location: Int, posts: Collection<Micropost>): Boolean {
+    fun addAll(location: Int, posts: List<Micropost>): Boolean {
         if (this.posts.addAll(location, posts)) {
             notifyItemRangeInserted(location, posts.size)
             return true
diff --git a/app/src/main/res/layout/_user_detail.xml b/app/src/main/res/layout/_user_detail.xml
index 55a934f..7d4cdbd 100644
--- a/app/src/main/res/layout/_user_detail.xml
+++ b/app/src/main/res/layout/_user_detail.xml
@@ -26,7 +26,7 @@
             android:layout_height="wrap_content">
 
             <ImageView
-                android:id="@+id/avatar"
+                android:id="@+id/img_avatar"
                 android:layout_width="@dimen/avatar_size_large"
                 android:layout_height="@dimen/avatar_size_large"
                 android:layout_alignParentStart="true"
@@ -36,14 +36,14 @@
                 />
 
             <TextView
-                android:id="@+id/userName"
+                android:id="@+id/tv_user_name"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_centerVertical="true"
-                android:layout_toEndOf="@+id/avatar"/>
+                android:layout_toEndOf="@+id/img_avatar"/>
 
             <Button
-                android:id="@+id/followBtn"
+                android:id="@+id/btn_follow"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_alignParentEnd="true"
@@ -57,42 +57,16 @@
             android:layout_marginTop="10dp"
             android:orientation="horizontal">
 
-            <LinearLayout
-                android:id="@+id/followings"
+            <TextView
+                android:id="@+id/tv_followings"
                 android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:layout_marginEnd="@dimen/margin_medium"
-                android:orientation="horizontal">
-
-                <TextView
-                    android:id="@+id/followingCnt"
-                    android:layout_width="wrap_content"
-                    android:layout_height="wrap_content"
-                    android:textStyle="bold"/>
-
-                <TextView
-                    android:layout_width="wrap_content"
-                    android:layout_height="wrap_content"
-                    android:text="@string/followings"/>
-            </LinearLayout>
+                android:layout_height="wrap_content"/>
 
-            <LinearLayout
-                android:id="@+id/followers"
+            <TextView
+                android:id="@+id/tv_followers"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:orientation="horizontal">
-
-                <TextView
-                    android:id="@+id/followerCnt"
-                    android:layout_width="wrap_content"
-                    android:layout_height="wrap_content"
-                    android:textStyle="bold"/>
-
-                <TextView
-                    android:layout_width="wrap_content"
-                    android:layout_height="wrap_content"
-                    android:text="@string/followers"/>
-            </LinearLayout>
+                android:layout_marginStart="@dimen/margin_small"/>
         </LinearLayout>
     </LinearLayout>
 </FrameLayout>
diff --git a/app/src/main/res/layout/_user_posts.xml b/app/src/main/res/layout/_user_posts.xml
index 832fd2e..a7de91a 100644
--- a/app/src/main/res/layout/_user_posts.xml
+++ b/app/src/main/res/layout/_user_posts.xml
@@ -8,7 +8,7 @@
     android:elevation="2dp">
 
     <android.support.v7.widget.RecyclerView
-        android:id="@+id/postRecyclerView"
+        android:id="@+id/list_post"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:clipToPadding="false"
diff --git a/app/src/main/res/layout/activity_login.xml b/app/src/main/res/layout/activity_login.xml
index 72c0bea..0bca3ff 100644
--- a/app/src/main/res/layout/activity_login.xml
+++ b/app/src/main/res/layout/activity_login.xml
@@ -25,7 +25,7 @@
             android:layout_height="wrap_content">
 
             <android.support.v7.widget.AppCompatEditText
-                android:id="@+id/emailEditText"
+                android:id="@+id/et_email"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:hint="@string/email"
@@ -37,7 +37,7 @@
             android:layout_height="wrap_content">
 
             <android.support.v7.widget.AppCompatEditText
-                android:id="@+id/passwordEditText"
+                android:id="@+id/et_password"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:hint="@string/password"
@@ -52,7 +52,7 @@
         android:background="@drawable/border_top">
 
         <Button
-            android:id="@+id/loginBtn"
+            android:id="@+id/btn_login"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignParentEnd="true"
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index bac79fc..525b877 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -8,12 +8,12 @@
     tools:context=".pages.main.MainActivity">
 
     <android.support.v4.widget.SwipeRefreshLayout
-        android:id="@+id/swipeRefreshLayout"
+        android:id="@+id/swipe_refresh"
         android:layout_width="match_parent"
         android:layout_height="match_parent">
 
         <android.support.v7.widget.RecyclerView
-            android:id="@+id/postRecyclerView"
+            android:id="@+id/list_post"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             android:clipToPadding="false"
@@ -26,7 +26,7 @@
         android:layout_alignParentBottom="true">
 
         <android.support.design.widget.FloatingActionButton
-            android:id="@+id/newMicropostBtn"
+            android:id="@+id/btn_new_micropost"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignParentEnd="true"
diff --git a/app/src/main/res/layout/activity_micropost_new.xml b/app/src/main/res/layout/activity_micropost_new.xml
index 5308e0b..0d84d24 100644
--- a/app/src/main/res/layout/activity_micropost_new.xml
+++ b/app/src/main/res/layout/activity_micropost_new.xml
@@ -6,7 +6,7 @@
     android:layout_height="match_parent">
 
     <EditText
-        android:id="@+id/postEditText"
+        android:id="@+id/et_post"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:background="@android:color/transparent"
@@ -25,7 +25,7 @@
         android:background="@drawable/border_top">
 
         <Button
-            android:id="@+id/postBtn"
+            android:id="@+id/btn_post"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignParentBottom="true"
diff --git a/app/src/main/res/layout/activity_related_user_list.xml b/app/src/main/res/layout/activity_related_user_list.xml
index 296d8c9..38fec4a 100644
--- a/app/src/main/res/layout/activity_related_user_list.xml
+++ b/app/src/main/res/layout/activity_related_user_list.xml
@@ -6,7 +6,7 @@
     android:layout_height="match_parent">
 
     <android.support.v7.widget.RecyclerView
-        android:id="@+id/userRecyclerView"
+        android:id="@+id/list_user"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:clipToPadding="false"
diff --git a/app/src/main/res/layout/activity_top.xml b/app/src/main/res/layout/activity_top.xml
index 7d284c8..8592b95 100644
--- a/app/src/main/res/layout/activity_top.xml
+++ b/app/src/main/res/layout/activity_top.xml
@@ -40,7 +40,7 @@
         android:paddingRight="72dp">
 
         <Button
-            android:id="@+id/signupBtn"
+            android:id="@+id/btn_signup"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_marginBottom="@dimen/margin_medium"
@@ -51,7 +51,7 @@
             android:textSize="@dimen/app_text_size_xlarge"/>
 
         <Button
-            android:id="@+id/loginBtn"
+            android:id="@+id/btn_login"
             android:theme="@style/LoginButton"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
diff --git a/app/src/main/res/layout/fragment_signup_email.xml b/app/src/main/res/layout/fragment_signup_email.xml
index 4a98f57..fa66b50 100644
--- a/app/src/main/res/layout/fragment_signup_email.xml
+++ b/app/src/main/res/layout/fragment_signup_email.xml
@@ -24,7 +24,7 @@
             android:layout_height="wrap_content">
 
             <android.support.v7.widget.AppCompatEditText
-                android:id="@+id/email"
+                android:id="@+id/et_email"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:hint="@string/email"
@@ -32,7 +32,7 @@
         </android.support.design.widget.TextInputLayout>
 
         <TextView
-            android:id="@+id/emailInvalid"
+            android:id="@+id/tv_email_invalid"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="@string/please_enter_a_valid_email"
@@ -46,11 +46,10 @@
         android:background="@drawable/border_top">
 
         <Button
-            android:id="@+id/emailNextBtn"
+            android:id="@+id/btn_next"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignParentEnd="true"
-            android:layout_alignParentRight="true"
             android:text="@string/next"/>
     </RelativeLayout>
 </RelativeLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/fragment_signup_full_name.xml b/app/src/main/res/layout/fragment_signup_full_name.xml
index b78c320..09211a3 100644
--- a/app/src/main/res/layout/fragment_signup_full_name.xml
+++ b/app/src/main/res/layout/fragment_signup_full_name.xml
@@ -25,7 +25,7 @@
             android:layout_height="wrap_content">
 
             <android.support.v7.widget.AppCompatEditText
-                android:id="@+id/fullName"
+                android:id="@+id/et_full_name"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:hint="@string/full_name"
@@ -33,7 +33,7 @@
         </android.support.design.widget.TextInputLayout>
 
         <TextView
-            android:id="@+id/fullNameInvalid"
+            android:id="@+id/tv_full_name_invalid"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="@string/full_name_must_be_longer_than_4_chars"
@@ -47,7 +47,7 @@
         android:background="@drawable/border_top">
 
         <Button
-            android:id="@+id/fullNameNextBtn"
+            android:id="@+id/btn_next"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignParentEnd="true"
diff --git a/app/src/main/res/layout/fragment_signup_password.xml b/app/src/main/res/layout/fragment_signup_password.xml
index 8c4dec4..f4bd36d 100644
--- a/app/src/main/res/layout/fragment_signup_password.xml
+++ b/app/src/main/res/layout/fragment_signup_password.xml
@@ -25,7 +25,7 @@
             android:layout_height="wrap_content">
 
             <android.support.v7.widget.AppCompatEditText
-                android:id="@+id/password"
+                android:id="@+id/et_password"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:hint="@string/password"
@@ -33,7 +33,7 @@
         </android.support.design.widget.TextInputLayout>
 
         <TextView
-            android:id="@+id/passwordInvalid"
+            android:id="@+id/tv_password_invalid"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="@string/password_must_be_longer_than_8_chars"
@@ -47,7 +47,7 @@
         android:background="@drawable/border_top">
 
         <Button
-            android:id="@+id/passwordNextBtn"
+            android:id="@+id/btn_next"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignParentEnd="true"
diff --git a/app/src/main/res/layout/item_posts.xml b/app/src/main/res/layout/item_posts.xml
index 44ccc52..0373a20 100644
--- a/app/src/main/res/layout/item_posts.xml
+++ b/app/src/main/res/layout/item_posts.xml
@@ -13,7 +13,7 @@
     android:paddingTop="@dimen/margin_small">
 
     <ImageView
-        android:id="@+id/avatar"
+        android:id="@+id/img_avatar"
         android:layout_width="@dimen/avatar_size_medium"
         android:layout_height="@dimen/avatar_size_medium"
         android:layout_marginEnd="@dimen/activity_horizontal_margin"
@@ -25,22 +25,22 @@
         android:layout_height="wrap_content">
 
         <TextView
-            android:id="@+id/userName"
+            android:id="@+id/tv_post_user_name"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:textStyle="bold"/>
 
         <com.github.curioustechizen.ago.RelativeTimeTextView
-            android:id="@+id/createdAt"
+            android:id="@+id/tv_post_created_at"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignParentEnd="true"
             tools:ignore="RelativeOverlap"/>
 
         <TextView
-            android:id="@+id/content"
+            android:id="@+id/tv_post_content"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:layout_below="@id/userName"/>
+            android:layout_below="@id/tv_post_user_name"/>
     </RelativeLayout>
 </LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/item_related_users.xml b/app/src/main/res/layout/item_related_users.xml
index 3eb69b7..2f74d67 100644
--- a/app/src/main/res/layout/item_related_users.xml
+++ b/app/src/main/res/layout/item_related_users.xml
@@ -13,7 +13,7 @@
     android:paddingTop="@dimen/margin_small">
 
     <ImageView
-        android:id="@+id/avatar"
+        android:id="@+id/img_avatar"
         android:layout_width="@dimen/avatar_size_medium"
         android:layout_height="@dimen/avatar_size_medium"
         android:layout_marginEnd="@dimen/activity_horizontal_margin"
@@ -25,13 +25,13 @@
         android:layout_height="wrap_content">
 
         <TextView
-            android:id="@+id/userName"
+            android:id="@+id/tv_user_name"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:textStyle="bold"/>
 
         <Button
-            android:id="@+id/followBtn"
+            android:id="@+id/btn_follow"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_alignParentEnd="true"
diff --git a/app/src/test/kotlin/com/hana053/micropost/pages/main/MainServiceTest.kt b/app/src/test/kotlin/com/hana053/micropost/pages/main/MainServiceTest.kt
index 1ecea00..048d9b4 100644
--- a/app/src/test/kotlin/com/hana053/micropost/pages/main/MainServiceTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/pages/main/MainServiceTest.kt
@@ -10,8 +10,7 @@ import com.nhaarman.mockito_kotlin.any
 import com.nhaarman.mockito_kotlin.doReturn
 import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
 import org.mockito.Mockito.`when`
 import rx.Observable
@@ -36,8 +35,8 @@ class MainServiceTest : RobolectricBaseTest() {
         mainService.loadNextFeed().subscribe()
         advance()
 
-        assertThat(postListAdapter.itemCount, `is`(1))
-        assertThat(postListAdapter.getFirstItemId(), `is`(TestMicropost.id))
+        assertThat(postListAdapter.itemCount).isEqualTo(1)
+        assertThat(postListAdapter.getFirstItemId()).isEqualTo(TestMicropost.id)
     }
 
     @Test
@@ -52,9 +51,9 @@ class MainServiceTest : RobolectricBaseTest() {
         mainService.loadNextFeed().subscribe()
         advance()
 
-        assertThat(postListAdapter.itemCount, `is`(3))
-        assertThat(postListAdapter.getFirstItemId(), `is`(3L))
-        assertThat(postListAdapter.getLastItemId(), `is`(1L))
+        assertThat(postListAdapter.itemCount).isEqualTo(3)
+        assertThat(postListAdapter.getFirstItemId()).isEqualTo(3)
+        assertThat(postListAdapter.getLastItemId()).isEqualTo(1)
     }
 
     @Test
@@ -76,8 +75,8 @@ class MainServiceTest : RobolectricBaseTest() {
         mainService.loadPrevFeed().subscribe()
         advance()
 
-        assertThat(postListAdapter.itemCount, `is`(1))
-        assertThat(postListAdapter.getFirstItemId(), `is`(TestMicropost.id))
+        assertThat(postListAdapter.itemCount).isEqualTo(1)
+        assertThat(postListAdapter.getFirstItemId()).isEqualTo(TestMicropost.id)
     }
 
     @Test
@@ -92,9 +91,9 @@ class MainServiceTest : RobolectricBaseTest() {
         mainService.loadPrevFeed().subscribe()
         advance()
 
-        assertThat(postListAdapter.itemCount, `is`(3))
-        assertThat(postListAdapter.getFirstItemId(), `is`(3L))
-        assertThat(postListAdapter.getLastItemId(), `is`(1L))
+        assertThat(postListAdapter.itemCount).isEqualTo(3)
+        assertThat(postListAdapter.getFirstItemId()).isEqualTo(3)
+        assertThat(postListAdapter.getLastItemId()).isEqualTo(1)
     }
 
     @Test
diff --git a/app/src/test/kotlin/com/hana053/micropost/pages/relateduserlist/followerlist/FollowerListServiceTest.kt b/app/src/test/kotlin/com/hana053/micropost/pages/relateduserlist/followerlist/FollowerListServiceTest.kt
index 0371889..f865484 100644
--- a/app/src/test/kotlin/com/hana053/micropost/pages/relateduserlist/followerlist/FollowerListServiceTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/pages/relateduserlist/followerlist/FollowerListServiceTest.kt
@@ -10,8 +10,7 @@ import com.nhaarman.mockito_kotlin.any
 import com.nhaarman.mockito_kotlin.doReturn
 import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
 import org.mockito.Mockito.`when`
 import rx.Observable
@@ -40,8 +39,8 @@ class FollowerListServiceTest : RobolectricBaseTest() {
         followerListService.listUsers(userId).subscribe()
         advance()
 
-        assertThat(relatedUserListAdapter.itemCount, `is`(1))
-        assertThat(relatedUserListAdapter.getLastItemId(), `is`(101L))
+        assertThat(relatedUserListAdapter.itemCount).isEqualTo(1)
+        assertThat(relatedUserListAdapter.getLastItemId()).isEqualTo(101)
     }
 
     @Test
@@ -59,8 +58,8 @@ class FollowerListServiceTest : RobolectricBaseTest() {
         followerListService.listUsers(userId).subscribe()
         advance()
 
-        assertThat(relatedUserListAdapter.itemCount, `is`(3))
-        assertThat(relatedUserListAdapter.getLastItemId(), `is`(101L))
+        assertThat(relatedUserListAdapter.itemCount).isEqualTo(3)
+        assertThat(relatedUserListAdapter.getLastItemId()).isEqualTo(101)
     }
 
     @Test
diff --git a/app/src/test/kotlin/com/hana053/micropost/pages/relateduserlist/followinglist/FollowingListServiceTest.kt b/app/src/test/kotlin/com/hana053/micropost/pages/relateduserlist/followinglist/FollowingListServiceTest.kt
index 51af71a..adf2e36 100644
--- a/app/src/test/kotlin/com/hana053/micropost/pages/relateduserlist/followinglist/FollowingListServiceTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/pages/relateduserlist/followinglist/FollowingListServiceTest.kt
@@ -10,8 +10,7 @@ import com.nhaarman.mockito_kotlin.any
 import com.nhaarman.mockito_kotlin.doReturn
 import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
 import org.mockito.Mockito.`when`
 import rx.Observable
@@ -40,8 +39,8 @@ class FollowingListServiceTest : RobolectricBaseTest() {
         followingListService.listUsers(userId).subscribe()
         advance()
 
-        assertThat(relatedUserListAdapter.itemCount, `is`(1))
-        assertThat(relatedUserListAdapter.getLastItemId(), `is`(101L))
+        assertThat(relatedUserListAdapter.itemCount).isEqualTo(1)
+        assertThat(relatedUserListAdapter.getLastItemId()).isEqualTo(101)
     }
 
     @Test
@@ -59,8 +58,8 @@ class FollowingListServiceTest : RobolectricBaseTest() {
         followingListService.listUsers(userId).subscribe()
         advance()
 
-        assertThat(relatedUserListAdapter.itemCount, `is`(3))
-        assertThat(relatedUserListAdapter.getLastItemId(), `is`(101L))
+        assertThat(relatedUserListAdapter.itemCount).isEqualTo(3)
+        assertThat(relatedUserListAdapter.getLastItemId()).isEqualTo(101)
     }
 
     @Test
diff --git a/app/src/test/kotlin/com/hana053/micropost/pages/signup/SignupServiceTest.kt b/app/src/test/kotlin/com/hana053/micropost/pages/signup/SignupServiceTest.kt
index 008f845..158598e 100644
--- a/app/src/test/kotlin/com/hana053/micropost/pages/signup/SignupServiceTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/pages/signup/SignupServiceTest.kt
@@ -8,13 +8,12 @@ import com.hana053.micropost.testing.EmptyResponseBody
 import com.hana053.micropost.testing.RobolectricBaseTest
 import com.hana053.micropost.testing.TestUser
 import com.nhaarman.mockito_kotlin.*
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
 import org.mockito.Mockito.`when`
 import org.robolectric.shadows.ShadowToast
+import retrofit2.HttpException
 import retrofit2.Response
-import retrofit2.adapter.rxjava.HttpException
 import rx.Observable
 
 
@@ -58,7 +57,7 @@ class SignupServiceTest : RobolectricBaseTest() {
         signupService.signup(signupRequest).subscribe()
         advance()
 
-        assertThat(ShadowToast.getTextOfLatestToast(), `is`("This email is already taken."))
+        assertThat(ShadowToast.getTextOfLatestToast()).isEqualTo("This email is already taken.")
         verify(loginService, never()).login(any(), any())
     }
 
diff --git a/app/src/test/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailServiceTest.kt b/app/src/test/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailServiceTest.kt
index 8fe1582..61acde6 100644
--- a/app/src/test/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailServiceTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/pages/usershow/detail/UserShowDetailServiceTest.kt
@@ -9,8 +9,7 @@ import com.nhaarman.mockito_kotlin.any
 import com.nhaarman.mockito_kotlin.doReturn
 import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
 import org.mockito.Mockito.`when`
 import rx.Observable
@@ -36,7 +35,7 @@ class UserShowDetailServiceTest : RobolectricBaseTest() {
         advance()
 
         verify(userInteractor).get(userId)
-        assertThat(user, `is`(TestUser))
+        assertThat(user).isEqualTo(TestUser)
     }
 
     @Test
diff --git a/app/src/test/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsServiceTest.kt b/app/src/test/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsServiceTest.kt
index f678c77..fe9e860 100644
--- a/app/src/test/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsServiceTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/pages/usershow/posts/UserShowPostsServiceTest.kt
@@ -10,8 +10,7 @@ import com.nhaarman.mockito_kotlin.any
 import com.nhaarman.mockito_kotlin.doReturn
 import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
 import org.mockito.Mockito.`when`
 import rx.Observable
@@ -39,8 +38,8 @@ class UserShowPostsServiceTest : RobolectricBaseTest() {
         userShowPostsService.loadPosts(userId).subscribe()
         advance()
 
-        assertThat(postListAdapter.itemCount, `is`(1))
-        assertThat(postListAdapter.getFirstItemId(), `is`(1L))
+        assertThat(postListAdapter.itemCount).isEqualTo(1)
+        assertThat(postListAdapter.getFirstItemId()).isEqualTo(1)
     }
 
     @Test
@@ -58,9 +57,9 @@ class UserShowPostsServiceTest : RobolectricBaseTest() {
         userShowPostsService.loadPosts(userId).subscribe()
         advance()
 
-        assertThat(postListAdapter.itemCount, `is`(3))
-        assertThat(postListAdapter.getFirstItemId(), `is`(3L))
-        assertThat(postListAdapter.getLastItemId(), `is`(1L))
+        assertThat(postListAdapter.itemCount).isEqualTo(3)
+        assertThat(postListAdapter.getFirstItemId()).isEqualTo(3)
+        assertThat(postListAdapter.getLastItemId()).isEqualTo(1)
     }
 
     @Test
diff --git a/app/src/test/kotlin/com/hana053/micropost/repository/AuthTokenRepositoryTest.kt b/app/src/test/kotlin/com/hana053/micropost/repository/AuthTokenRepositoryTest.kt
index 0916aba..4a6ea1b 100644
--- a/app/src/test/kotlin/com/hana053/micropost/repository/AuthTokenRepositoryTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/repository/AuthTokenRepositoryTest.kt
@@ -2,28 +2,25 @@ package com.hana053.micropost.repository
 
 import android.preference.PreferenceManager
 import com.hana053.micropost.testing.RobolectricBaseTest
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.CoreMatchers.nullValue
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
-import org.robolectric.RuntimeEnvironment
 
 class AuthTokenRepositoryTest : RobolectricBaseTest() {
 
-    private val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(RuntimeEnvironment.application)
+    private val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(app)
     private val authTokenRepository = AuthTokenRepositoryImpl(sharedPreferences)
 
     @Test
     fun shouldSaveAuthToken() {
         authTokenRepository.set("my token")
-        assertThat(authTokenRepository.get(), `is`("my token"))
+        assertThat(authTokenRepository.get()).isEqualTo("my token")
     }
 
     @Test
     fun shouldClearAuthToken() {
         authTokenRepository.set("my token")
         authTokenRepository.clear()
-        assertThat(authTokenRepository.get(), nullValue())
+        assertThat(authTokenRepository.get()).isNullOrEmpty()
     }
 
 }
\ No newline at end of file
diff --git a/app/src/test/kotlin/com/hana053/micropost/service/AuthServiceTest.kt b/app/src/test/kotlin/com/hana053/micropost/service/AuthServiceTest.kt
index 1223ef8..a4c9f45 100644
--- a/app/src/test/kotlin/com/hana053/micropost/service/AuthServiceTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/service/AuthServiceTest.kt
@@ -7,8 +7,7 @@ import com.hana053.micropost.testing.jwtForUserId1
 import com.nhaarman.mockito_kotlin.doReturn
 import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
 import org.mockito.Mockito.`when`
 
@@ -28,10 +27,10 @@ class AuthServiceTest : RobolectricBaseTest() {
             .doReturn(jwtForUserId1)
 
         val user1 = TestUser.copy(id = 1)
-        assertThat(authService.isMyself(user1), `is`(true))
+        assertThat(authService.isMyself(user1)).isTrue()
 
         val user2 = TestUser.copy(id = 2)
-        assertThat(authService.isMyself(user2), `is`(false))
+        assertThat(authService.isMyself(user2)).isFalse()
     }
 
     @Test
@@ -44,13 +43,13 @@ class AuthServiceTest : RobolectricBaseTest() {
 
     @Test
     fun shouldForceLogoutWhenAuthTokenIsEmpty() {
-        assertThat(authService.auth(), `is`(false))
+        assertThat(authService.auth()).isFalse()
         verify(navigator).navigateToTop()
     }
 
     @Test
     fun shouldJustReturnTrueWhenAuthenticated() {
         `when`(authTokenRepository.get()).doReturn("test token")
-        assertThat(authService.auth(), `is`(true))
+        assertThat(authService.auth()).isTrue()
     }
 }
\ No newline at end of file
diff --git a/app/src/test/kotlin/com/hana053/micropost/service/HttpErrorHandlerTest.kt b/app/src/test/kotlin/com/hana053/micropost/service/HttpErrorHandlerTest.kt
index 0ec3314..9b8384d 100644
--- a/app/src/test/kotlin/com/hana053/micropost/service/HttpErrorHandlerTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/service/HttpErrorHandlerTest.kt
@@ -4,14 +4,13 @@ import com.hana053.micropost.testing.EmptyResponseBody
 import com.hana053.micropost.testing.RobolectricBaseTest
 import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Before
 import org.junit.Test
 import org.robolectric.shadows.ShadowLog
 import org.robolectric.shadows.ShadowToast
+import retrofit2.HttpException
 import retrofit2.Response
-import retrofit2.adapter.rxjava.HttpException
 import java.net.ConnectException
 import java.net.SocketTimeoutException
 
@@ -29,32 +28,32 @@ class HttpErrorHandlerTest : RobolectricBaseTest() {
     @Test
     fun shouldHandleSocketTimeoutException() {
         httpErrorHandler.handleError(SocketTimeoutException())
-        assertThat(ShadowToast.getTextOfLatestToast(), `is`("Connection timed out."))
+        assertThat(ShadowToast.getTextOfLatestToast()).isEqualTo("Connection timed out.")
     }
 
     @Test
     fun shouldHandleConnectException() {
         httpErrorHandler.handleError(ConnectException())
-        assertThat(ShadowToast.getTextOfLatestToast(), `is`("Cannot connect to server."))
+        assertThat(ShadowToast.getTextOfLatestToast()).isEqualTo("Cannot connect to server.")
     }
 
     @Test
     fun shouldHandle401Error() {
         httpErrorHandler.handleError(createHttpException(401))
-        assertThat(ShadowToast.getTextOfLatestToast(), `is`("Please sign in."))
+        assertThat(ShadowToast.getTextOfLatestToast()).isEqualTo("Please sign in.")
         verify(authService).logout()
     }
 
     @Test
     fun shouldHandle500Error() {
         httpErrorHandler.handleError(createHttpException(500))
-        assertThat(ShadowToast.getTextOfLatestToast(), `is`("Something bad happened."))
+        assertThat(ShadowToast.getTextOfLatestToast()).isEqualTo("Something bad happened.")
     }
 
     @Test
     fun shouldHandleUnknownError() {
         httpErrorHandler.handleError(RuntimeException())
-        assertThat(ShadowToast.getTextOfLatestToast(), `is`("Something bad happened."))
+        assertThat(ShadowToast.getTextOfLatestToast()).isEqualTo("Something bad happened.")
     }
 
     private fun createHttpException(status: Int): HttpException {
diff --git a/app/src/test/kotlin/com/hana053/micropost/service/LoginServiceTest.kt b/app/src/test/kotlin/com/hana053/micropost/service/LoginServiceTest.kt
index 08f512d..abb5daf 100644
--- a/app/src/test/kotlin/com/hana053/micropost/service/LoginServiceTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/service/LoginServiceTest.kt
@@ -8,13 +8,12 @@ import com.nhaarman.mockito_kotlin.any
 import com.nhaarman.mockito_kotlin.doReturn
 import com.nhaarman.mockito_kotlin.mock
 import com.nhaarman.mockito_kotlin.verify
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Test
 import org.mockito.Mockito.`when`
 import org.robolectric.shadows.ShadowToast
+import retrofit2.HttpException
 import retrofit2.Response
-import retrofit2.adapter.rxjava.HttpException
 import rx.Observable
 
 
@@ -49,7 +48,7 @@ class LoginServiceTest : RobolectricBaseTest() {
         loginService.login("test@test.com", "secret").subscribe()
         advance()
 
-        assertThat(ShadowToast.getTextOfLatestToast(), `is`("Email or Password is wrong."))
+        assertThat(ShadowToast.getTextOfLatestToast()).isEqualTo("Email or Password is wrong.")
     }
 
     @Test
diff --git a/app/src/test/kotlin/com/hana053/micropost/service/NavigatorTest.kt b/app/src/test/kotlin/com/hana053/micropost/service/NavigatorTest.kt
index 9eae4c7..7f4c3a2 100644
--- a/app/src/test/kotlin/com/hana053/micropost/service/NavigatorTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/service/NavigatorTest.kt
@@ -11,8 +11,7 @@ import com.hana053.micropost.pages.signup.SignupActivity
 import com.hana053.micropost.pages.usershow.UserShowActivity
 import com.hana053.micropost.testing.RobolectricBaseTest
 import com.hana053.micropost.testing.TestUser
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Before
 import org.junit.Test
 import org.robolectric.Robolectric
@@ -39,8 +38,8 @@ class NavigatorTest : RobolectricBaseTest() {
         val shadow = Shadows.shadowOf(activity)
         val intent = shadow.nextStartedActivity
 
-        assertThat(intent.component.className, `is`(UserShowActivity::class.java.name))
-        assertThat(intent.extras.getLong(UserShowActivity.KEY_USER_ID), `is`(1L))
+        assertThat(intent.component.className).isEqualTo(UserShowActivity::class.java.name)
+        assertThat(intent.extras.getLong(UserShowActivity.KEY_USER_ID)).isEqualTo(1)
     }
 
     @Test
@@ -50,7 +49,7 @@ class NavigatorTest : RobolectricBaseTest() {
         val shadow = Shadows.shadowOf(activity)
         val intent = shadow.nextStartedActivity
 
-        assertThat(intent.component.className, `is`(MainActivity::class.java.name))
+        assertThat(intent.component.className).isEqualTo(MainActivity::class.java.name)
     }
 
     @Test
@@ -60,7 +59,7 @@ class NavigatorTest : RobolectricBaseTest() {
         val shadow = Shadows.shadowOf(activity)
         val intent = shadow.nextStartedActivity
 
-        assertThat(intent.component.className, `is`(SignupActivity::class.java.name))
+        assertThat(intent.component.className).isEqualTo(SignupActivity::class.java.name)
     }
 
     @Test
@@ -70,7 +69,7 @@ class NavigatorTest : RobolectricBaseTest() {
         val shadow = Shadows.shadowOf(activity)
         val intent = shadow.nextStartedActivity
 
-        assertThat(intent.component.className, `is`(LoginActivity::class.java.name))
+        assertThat(intent.component.className).isEqualTo(LoginActivity::class.java.name)
     }
 
     @Test
@@ -80,12 +79,10 @@ class NavigatorTest : RobolectricBaseTest() {
         val shadow = Shadows.shadowOf(activity)
         val intent = shadow.nextStartedActivity
 
-        assertThat(intent.component.className, `is`(RelatedUserListActivity::class.java.name))
-        assertThat(intent.extras.getLong(RelatedUserListActivity.KEY_USER_ID), `is`(1L))
-        assertThat(
-            intent.extras.getSerializable(RelatedUserListActivity.KEY_LIST_TYPE) as RelatedUserListActivity.ListType,
-            `is`(RelatedUserListActivity.ListType.FOLLOWING)
-        )
+        assertThat(intent.component.className).isEqualTo(RelatedUserListActivity::class.java.name)
+        assertThat(intent.extras.getLong(RelatedUserListActivity.KEY_USER_ID)).isEqualTo(1)
+        assertThat(intent.extras.getSerializable(RelatedUserListActivity.KEY_LIST_TYPE) as RelatedUserListActivity.ListType)
+            .isEqualTo(RelatedUserListActivity.ListType.FOLLOWING)
     }
 
     @Test
@@ -95,12 +92,10 @@ class NavigatorTest : RobolectricBaseTest() {
         val shadow = Shadows.shadowOf(activity)
         val intent = shadow.nextStartedActivity
 
-        assertThat(intent.component.className, `is`(RelatedUserListActivity::class.java.name))
-        assertThat(intent.extras.getLong(RelatedUserListActivity.KEY_USER_ID), `is`(1L))
-        assertThat(
-            intent.extras.getSerializable(RelatedUserListActivity.KEY_LIST_TYPE) as RelatedUserListActivity.ListType,
-            `is`(RelatedUserListActivity.ListType.FOLLOWER)
-        )
+        assertThat(intent.component.className).isEqualTo(RelatedUserListActivity::class.java.name)
+        assertThat(intent.extras.getLong(RelatedUserListActivity.KEY_USER_ID)).isEqualTo(1)
+        assertThat(intent.extras.getSerializable(RelatedUserListActivity.KEY_LIST_TYPE) as RelatedUserListActivity.ListType)
+            .isEqualTo(RelatedUserListActivity.ListType.FOLLOWER)
     }
 
     @Test
@@ -110,14 +105,14 @@ class NavigatorTest : RobolectricBaseTest() {
         val shadow = Shadows.shadowOf(activity)
         val intent = shadow.nextStartedActivity
 
-        assertThat(intent.component.className, `is`(MicropostNewActivity::class.java.name))
+        assertThat(intent.component.className).isEqualTo(MicropostNewActivity::class.java.name)
 
         shadow.receiveResult(
             Intent(activity, MicropostNewActivity::class.java),
             Activity.RESULT_OK,
             Intent()
         )
-        assertThat(activity.postReceived, `is`(true))
+        assertThat(activity.postReceived).isTrue()
     }
 
     class TestActivity : Activity() {
diff --git a/app/src/test/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnServiceTest.kt b/app/src/test/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnServiceTest.kt
index e968554..65ea6a7 100644
--- a/app/src/test/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnServiceTest.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/shared/followbtn/FollowBtnServiceTest.kt
@@ -11,8 +11,7 @@ import com.hana053.micropost.testing.RobolectricBaseTest
 import com.hana053.micropost.testing.TestUser
 import com.nhaarman.mockito_kotlin.doReturn
 import com.nhaarman.mockito_kotlin.mock
-import org.hamcrest.CoreMatchers.`is`
-import org.hamcrest.MatcherAssert.assertThat
+import org.assertj.core.api.Assertions.assertThat
 import org.junit.Before
 import org.junit.Test
 import org.mockito.Mockito.`when`
@@ -48,12 +47,12 @@ class FollowBtnServiceTest : RobolectricBaseTest() {
         view.render(TestUser.copy(id = userId, isFollowedByMe = false))
 
         // just confirm that Follow is shown
-        assertThat(view.isFollowState(), `is`(true))
+        assertThat(view.isFollowState()).isTrue()
 
         followBtnService.handleFollowBtnClicks(view).subscribe()
         advance()
 
-        assertThat(view.isFollowState(), `is`(false))
+        assertThat(view.isFollowState()).isFalse()
     }
 
     @Test
@@ -66,11 +65,11 @@ class FollowBtnServiceTest : RobolectricBaseTest() {
         view.render(TestUser.copy(id = userId, isFollowedByMe = true))
 
         // just confirm that Unfollow is shown
-        assertThat(view.isFollowState(), `is`(false))
+        assertThat(view.isFollowState()).isFalse()
 
         followBtnService.handleFollowBtnClicks(view).subscribe()
         advance()
 
-        assertThat(view.isFollowState(), `is`(true))
+        assertThat(view.isFollowState()).isTrue()
     }
 }
\ No newline at end of file
diff --git a/app/src/test/kotlin/com/hana053/micropost/testing/TestSchedulerProxy.kt b/app/src/test/kotlin/com/hana053/micropost/testing/TestSchedulerProxy.kt
index 8bad9b3..12e7ab1 100644
--- a/app/src/test/kotlin/com/hana053/micropost/testing/TestSchedulerProxy.kt
+++ b/app/src/test/kotlin/com/hana053/micropost/testing/TestSchedulerProxy.kt
@@ -28,9 +28,7 @@ internal class TestSchedulerProxy {
             }
         }
 
-        fun get(): TestSchedulerProxy {
-            return INSTANCE
-        }
+        fun get() = INSTANCE
     }
 
 }
diff --git a/app/src/testShared/kotlin/com/hana053/micropost/testing/EmptyResponseBody.kt b/app/src/testShared/kotlin/com/hana053/micropost/testing/EmptyResponseBody.kt
index b4240b4..c55654b 100644
--- a/app/src/testShared/kotlin/com/hana053/micropost/testing/EmptyResponseBody.kt
+++ b/app/src/testShared/kotlin/com/hana053/micropost/testing/EmptyResponseBody.kt
@@ -1,19 +1,11 @@
 package com.hana053.micropost.testing
 
-import okhttp3.MediaType
 import okhttp3.ResponseBody
-import okio.BufferedSource
 
 class EmptyResponseBody : ResponseBody() {
-    override fun contentType(): MediaType? {
-        return null
-    }
 
-    override fun contentLength(): Long {
-        return 0
-    }
+    override fun contentType() = null
+    override fun contentLength(): Long = 0
+    override fun source() = null
 
-    override fun source(): BufferedSource? {
-        return null
-    }
 }
diff --git a/app/src/testShared/kotlin/com/hana053/micropost/testing/InjectableTest.kt b/app/src/testShared/kotlin/com/hana053/micropost/testing/InjectableTest.kt
index 7c64fd7..d36b8bd 100644
--- a/app/src/testShared/kotlin/com/hana053/micropost/testing/InjectableTest.kt
+++ b/app/src/testShared/kotlin/com/hana053/micropost/testing/InjectableTest.kt
@@ -13,10 +13,10 @@ interface InjectableTest {
 
     @Before
     fun resetSharedPreferences() {
-        val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(app)
-        val editor = sharedPreferences.edit()
-        editor.clear()
-        editor.apply()
+        PreferenceManager.getDefaultSharedPreferences(app).edit()
+            .clear()
+            .apply()
+
     }
 
     fun overrideAppBindings(init: Kodein.Builder.() -> Unit) {
diff --git a/build.gradle b/build.gradle
index 2881c14..06d652e 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,24 +1,33 @@
 buildscript {
     ext {
-        android_support_version = '25.1.1'
-        kotlin_version = '1.0.6'
-        kodein_version = '3.2.0'
-        rxbinding_version = '1.0.0'
-        rxlifecycle_version = '1.0'
-        retrofit_version = '2.1.0'
-        robolectric_version = '3.2.2'
+        android_ago_version = '1.3.2'
         android_support_test_version = '0.5'
+        android_support_version = '25.3.0'
+        assertj_android_version = '1.1.1'
+        assertj_version = '3.6.2'
+        dexmaker_mockito_version = '2.2.0'
         espresso_version = '2.2.2'
         hamcrest_version = '1.3'
-        mockito_version = '2.7.5'
-        mockito_kotlin_version = '1.2.0'
+        jose_jwt_version = '4.34'
+        kodein_version = '3.2.0'
+        kotlin_version = '1.0.6'
         leakcanary_version = '1.5'
+        mockito_kotlin_version = '1.3.0'
+        mockito_version = '2.7.18'
+        okhttp_version = '3.6.0'
+        picasso_version = '2.5.2'
+        retrofit_version = '2.2.0'
+        robolectric_version = '3.3.1'
+        rxbinding_version = '1.0.1'
+        rxlifecycle_version = '1.0'
+        testbutler_version = '1.2.0'
+        timber_version = '4.5.1'
     }
     repositories {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.2.3'
+        classpath 'com.android.tools.build:gradle:2.3.0'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -26,7 +35,6 @@ buildscript {
 allprojects {
     repositories {
         jcenter()
-        maven { url "https://jitpack.io" }
     }
 }
 
diff --git a/gradle.properties.ci.example b/gradle.properties.ci.example
index 7cafc01..226932e 100644
--- a/gradle.properties.ci.example
+++ b/gradle.properties.ci.example
@@ -1 +1,2 @@
 micropost.apiUrl="http://localhost/api/"
+
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index ba49a33..8d22052 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-3.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-3.4-all.zip