Matcher that allows the user to match the entries of a map

tomwhoiscontrary · tomwhoiscontrary · commit 39145e5aa083 · 2015-10-31T21:56:04.000Z
diff --git a/hamcrest-library/src/main/java/org/hamcrest/Matchers.java b/hamcrest-library/src/main/java/org/hamcrest/Matchers.java
@@ -1068,6 +1068,19 @@ public static <K, V> org.hamcrest.Matcher<java.util.Map<? extends K,? extends V>
     return org.hamcrest.collection.IsMapContaining.<K,V>hasEntry(key, value);
   }
 
+  /**
+   * Creates a matcher for {@link java.util.Map}s matching when the examined {@link java.util.Map}'s set of entries
+   * satisfies the specified <code>entriesMatcher</code>.
+   * For example:
+   * <pre>assertThat(myMap, hasEntries(hasSize(2)))</pre>
+   *
+   * @param entriesMatcher
+   *     the matcher that must be satisfied by the set of entries
+   */
+  public static <K, V> org.hamcrest.Matcher<java.util.Map<? extends K,? extends V>> hasEntries(Matcher<? super java.util.Set<? extends java.util.Map.Entry<? extends K, ? extends V>>> entriesMatcher) {
+    return org.hamcrest.collection.IsMapWithEntries.hasEntries(entriesMatcher);
+  }
+
   /**
    * Creates a matcher for {@link java.util.Map}s matching when the examined {@link java.util.Map} contains
    * at least one key that satisfies the specified matcher.
diff --git a/hamcrest-library/src/main/java/org/hamcrest/collection/IsMapWithEntries.java b/hamcrest-library/src/main/java/org/hamcrest/collection/IsMapWithEntries.java
@@ -0,0 +1,33 @@
+package org.hamcrest.collection;
+
+import org.hamcrest.FeatureMatcher;
+import org.hamcrest.Matcher;
+
+import java.util.Map;
+import java.util.Set;
+
+public class IsMapWithEntries<K, V> extends FeatureMatcher<Map<? extends K, ? extends V>, Set<? extends Map.Entry<? extends K, ? extends V>>> {
+
+    public IsMapWithEntries(Matcher<? super Set<? extends Map.Entry<? extends K, ? extends V>>> entriesMatcher) {
+        super(entriesMatcher, "a map with entries", "map entries");
+    }
+
+    @Override
+    protected Set<? extends Map.Entry<? extends K, ? extends V>> featureValueOf(Map<? extends K, ? extends V> actual) {
+        return actual.entrySet();
+    }
+
+    /**
+     * Creates a matcher for {@link Map}s matching when the examined {@link Map}'s set of entries
+     * satisfies the specified <code>entriesMatcher</code>.
+     * For example:
+     * <pre>assertThat(myMap, hasEntries(hasSize(2)))</pre>
+     *
+     * @param entriesMatcher
+     *     the matcher that must be satisfied by the set of entries
+     */
+    public static <K, V> Matcher<Map<? extends K, ? extends V>> hasEntries(Matcher<? super Set<? extends Map.Entry<? extends K, ? extends V>>> entriesMatcher) {
+        return new IsMapWithEntries<>(entriesMatcher);
+    }
+
+}
diff --git a/hamcrest-library/src/test/java/org/hamcrest/collection/IsMapWithEntriesTest.java b/hamcrest-library/src/test/java/org/hamcrest/collection/IsMapWithEntriesTest.java
@@ -0,0 +1,34 @@
+package org.hamcrest.collection;
+
+import org.hamcrest.AbstractMatcherTest;
+import org.hamcrest.Matcher;
+import org.hamcrest.Matchers;
+
+import java.util.Collections;
+
+import static org.hamcrest.collection.IsMapWithEntries.hasEntries;
+
+public class IsMapWithEntriesTest extends AbstractMatcherTest {
+
+    @Override
+    protected Matcher<?> createMatcher() {
+        return hasEntries(Matchers.empty());
+    }
+
+    public void testDoesNotMatchNull() {
+        assertMismatchDescription("was null", hasEntries(Matchers.empty()), null);
+    }
+
+    public void testDoesNotMatchAMapWhoseEntriesDoNotSatisfyTheEntriesMatcher() {
+        assertMismatchDescription("map entries collection size was <0>", hasEntries(Matchers.hasSize(1)), Collections.emptyMap());
+    }
+
+    public void testMatchesAMapWhoseEntriesSatisfyTheEntriesMatcher() {
+        assertMatches(hasEntries(Matchers.hasSize(1)), Collections.singletonMap("k", "v"));
+    }
+
+    public void testHasReadableDescription() {
+        assertDescription("a map with entries an empty collection", hasEntries(Matchers.empty()));
+    }
+
+}
