Fix datetime test.

tests/corelib/date_time_test.dart

Index: tests/corelib/date_time_test.dart
diff --git a/tests/corelib/date_time_test.dart b/tests/corelib/date_time_test.dart
index 7c2940a4c5723f8e6c12366fae090710abe418d7..05d344459c01a77df6232c2f1c314fd22dc48a7f 100644
--- a/tests/corelib/date_time_test.dart
+++ b/tests/corelib/date_time_test.dart
@@ -44,7 +44,7 @@ void testMicrosecondsSinceEpoch() {
 
   if (!supportsMicroseconds) return;

[Lasse Reichstein Nielsen, 2015/12/09 14:54:29]

Still don't get why the test above works if microseconds are not supported, but
the one below does not.
In both cases you are creating a new DateTime from the microsecondsSinceEpoch of
another DateTime object, which should always give equal DateTime objects.

[floitsch, 2015/12/09 19:24:17]

Added a comment.

   dt1 = new DateTime.now();
-  microsecondsSinceEpoch = dt1.millisecondsSinceEpoch;
+  microsecondsSinceEpoch = dt1.microsecondsSinceEpoch;
   dt2 = new DateTime.fromMicrosecondsSinceEpoch(microsecondsSinceEpoch);
   Expect.equals(microsecondsSinceEpoch, dt2.microsecondsSinceEpoch);
 }