Add isNotEmpty to core_matchers.

pkg/matcher/lib/src/core_matchers.dart

Index: pkg/matcher/lib/src/core_matchers.dart
diff --git a/pkg/matcher/lib/src/core_matchers.dart b/pkg/matcher/lib/src/core_matchers.dart
index c3c996d908f27b76033061e179bd73530abe8e45..baf0ee05579682ef7d2655f71ea45f2fc8d77ca2 100644
--- a/pkg/matcher/lib/src/core_matchers.dart
+++ b/pkg/matcher/lib/src/core_matchers.dart
@@ -26,6 +26,22 @@ class _Empty extends Matcher {
   Description describe(Description description) => description.add('empty');
 }
 
+/// Returns a matcher that matches non-empty strings, maps or iterables
+// (including collections).

[Lasse Reichstein Nielsen, 2014/11/27 15:22:46]

Second line isn't part of dartdoc-comment.

Document that this is based on the `isNotEmpty` property of the item, so if
something implements inconsistent `isEmpty`, `isNotEmpty` and `length`, it's
clear what is being tested.

[blackhc, 2014/11/28 16:12:29]

Done.

+const Matcher isNotEmpty = const _NotEmpty();
+
+class _NotEmpty extends Matcher {
+  const _NotEmpty();
+  bool matches(item, Map matchState) {
+    if (item is Map || item is Iterable || item is String) {

[dskloet, 2014/11/27 15:27:53]

return (item is Map || item is Iterable || item is String) && item.isNotEmpty;

[blackhc, 2014/11/28 16:12:29]

Done.

+      return item.isNotEmpty;
+    } else {
+      return false;
+    }
+  }
+  Description describe(Description description) => description.add('non-empty');
+}
+
 /// A matcher that matches any null value.
 const Matcher isNull = const _IsNull();