diff --git a/circle.yml b/circle.yml
index ebfa4c58f..f18e5345c 100644
--- a/circle.yml
+++ b/circle.yml
@@ -4,7 +4,7 @@ machine:
 
 dependencies:
   pre:
-    - cd /usr/local && sudo rm -rf go && curl https://storage.googleapis.com/golang/go1.4.1.linux-amd64.tar.gz | sudo tar -xz && sudo chmod a+w go/src/path/filepath
+    - cd /usr/local && sudo rm -rf go && curl https://storage.googleapis.com/golang/go1.4.2.linux-amd64.tar.gz | sudo tar -xz && sudo chmod a+w go/src/path/filepath
   post:
     - npm install --global node-gyp
     - cd node-syscall && node-gyp rebuild && mkdir -p ~/.node_libraries/ && cp build/Release/syscall.node ~/.node_libraries/syscall.node
@@ -12,3 +12,4 @@ dependencies:
 test:
   override:
     - ./gopherjs test --short --minify github.com/gopherjs/gopherjs/tests github.com/gopherjs/gopherjs/js archive/tar archive/zip bufio bytes compress/bzip2 compress/flate compress/gzip compress/lzw compress/zlib container/heap container/list container/ring crypto/aes crypto/cipher crypto/des crypto/dsa crypto/ecdsa crypto/elliptic crypto/hmac crypto/md5 crypto/rand crypto/rc4 crypto/rsa crypto/sha1 crypto/sha256 crypto/sha512 crypto/subtle crypto/x509 database/sql database/sql/driver debug/dwarf debug/elf debug/gosym debug/macho debug/pe encoding/ascii85 encoding/asn1 encoding/base32 encoding/base64 encoding/binary encoding/csv encoding/gob encoding/hex encoding/json encoding/pem encoding/xml errors expvar flag fmt go/ast go/doc go/format go/parser go/printer go/scanner go/token hash/adler32 hash/crc32 hash/crc64 hash/fnv html html/template image image/color image/draw image/gif image/jpeg image/png index/suffixarray io io/ioutil math math/big math/cmplx math/rand mime mime/multipart net/http/cookiejar net/http/fcgi net/mail net/rpc/jsonrpc net/textproto net/url path path/filepath reflect regexp regexp/syntax sort strconv strings sync sync/atomic testing/quick text/scanner text/tabwriter text/template text/template/parse time unicode unicode/utf16 unicode/utf8
+    - go test -v -race ./...
diff --git a/compiler/prelude/jsmapping.go b/compiler/prelude/jsmapping.go
index 7c60b7d08..38874daec 100644
--- a/compiler/prelude/jsmapping.go
+++ b/compiler/prelude/jsmapping.go
@@ -245,6 +245,9 @@ var $internalize = function(v, t, recv) {
     if (v === null) {
       return $ifaceNil;
     }
+    if (v === undefined) {
+      return new $jsObjectPtr(undefined);
+    }
     switch (v.constructor) {
     case Int8Array:
       return new ($sliceType($Int8))(v);
diff --git a/compiler/prelude/prelude.go b/compiler/prelude/prelude.go
index 05b090b40..5427c2498 100644
--- a/compiler/prelude/prelude.go
+++ b/compiler/prelude/prelude.go
@@ -413,6 +413,9 @@ var $interfaceIsEqual = function(a, b) {
   if (a.constructor !== b.constructor) {
     return false;
   }
+  if (a.constructor === $jsObjectPtr) {
+    return a.object === b.object;
+  }
   if (!a.constructor.comparable) {
     $throwRuntimeError("comparing uncomparable type " + a.constructor.string);
   }
diff --git a/js/js_test.go b/js/js_test.go
index 71fdad905..754fb1a1b 100644
--- a/js/js_test.go
+++ b/js/js_test.go
@@ -302,6 +302,31 @@ func TestEquality(t *testing.T) {
 	}
 }
 
+func TestUndefinedEquality(t *testing.T) {
+	var ui interface{} = js.Undefined
+	if ui != js.Undefined {
+		t.Fail()
+	}
+}
+
+func TestInterfaceEquality(t *testing.T) {
+	o := js.Global.Get("Object").New()
+	var i interface{} = o
+	if i != o {
+		t.Fail()
+	}
+}
+
+func TestUndefinedInternalization(t *testing.T) {
+	undefinedEqualsJsUndefined := func(i interface{}) bool {
+		return i == js.Undefined
+	}
+	js.Global.Set("undefinedEqualsJsUndefined", undefinedEqualsJsUndefined)
+	if !js.Global.Call("eval", "(undefinedEqualsJsUndefined(undefined))").Bool() {
+		t.Fail()
+	}
+}
+
 func TestSameFuncWrapper(t *testing.T) {
 	a := func(_ string) {} // string argument to force wrapping
 	b := func(_ string) {} // string argument to force wrapping