| Index: pkg/unittest/core_matchers.dart | 
| diff --git a/pkg/unittest/core_matchers.dart b/pkg/unittest/core_matchers.dart | 
| index e71e49176baa4e0a938b7c04fcabcd1f19e87705..add80a5f18ef0fd283b7ba6148b1dff8739b91c4 100644 | 
| --- a/pkg/unittest/core_matchers.dart | 
| +++ b/pkg/unittest/core_matchers.dart | 
| @@ -141,7 +141,7 @@ class _DeepMatcher extends BaseMatcher { | 
| } else if (expected.length != actual.length) { | 
| reason = new StringDescription('different map lengths'); | 
| } else { | 
| -          for (var key in expected.getKeys()) { | 
| +          for (var key in expected.keys) { | 
| if (!actual.containsKey(key)) { | 
| reason = new StringDescription('missing map key '); | 
| reason.addDescriptionOf(key); | 
|  |