Get rid of "==" in Expectation.

client/tests/client/observable/ChangeEventTests.dart

Index: client/tests/client/observable/ChangeEventTests.dart
diff --git a/client/tests/client/observable/ChangeEventTests.dart b/client/tests/client/observable/ChangeEventTests.dart
index da4bc2830868878fd38369f3e918ea41a4a7671d..1ae12b47490649e56e0aa3fc46534587f2b922ad 100644
--- a/client/tests/client/observable/ChangeEventTests.dart
+++ b/client/tests/client/observable/ChangeEventTests.dart
@@ -14,17 +14,17 @@ class ChangeEventTests extends ObservableTestSetBase {
     // create property, list, global and check the proper initialization.
     final target = new AbstractObservable();
 
-    checkEvent(new ChangeEvent.property(target, "pK", 33, "12"),
-        target, "pK", null, ChangeEvent.UPDATE, 33, "12");
+    checkEvent(new ChangeEvent.property(target, 'pK', 33, '12'),
+        target, 'pK', null, ChangeEvent.UPDATE, 33, '12');
 
-    checkEvent(new ChangeEvent.list(target, ChangeEvent.UPDATE, 3, 33, "12"),
-        target, null, 3, ChangeEvent.UPDATE, 33, "12");
+    checkEvent(new ChangeEvent.list(target, ChangeEvent.UPDATE, 3, 33, '12'),
+        target, null, 3, ChangeEvent.UPDATE, 33, '12');
 
     checkEvent(new ChangeEvent.list(target, ChangeEvent.INSERT, 3, 33, null),
         target, null, 3, ChangeEvent.INSERT, 33, null);
 
-    checkEvent(new ChangeEvent.list(target, ChangeEvent.REMOVE, 3, null, "12"),
-        target, null, 3, ChangeEvent.REMOVE, null, "12");
+    checkEvent(new ChangeEvent.list(target, ChangeEvent.REMOVE, 3, null, '12'),
+        target, null, 3, ChangeEvent.REMOVE, null, '12');
 
     checkEvent(new ChangeEvent.list(target, ChangeEvent.GLOBAL, 0, null, null),
         target, null, 0, ChangeEvent.GLOBAL, null, null);