Teach dart_package to understand the packages/ subdirectory

third_party/dart-packages/matcher/matcher/src/map_matchers.dart

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library matcher.map_matchers;
-
-import 'interfaces.dart';
-import 'util.dart';
-
-/// Returns a matcher which matches maps containing the given [value].
-Matcher containsValue(value) => new _ContainsValue(value);
-
-class _ContainsValue extends Matcher {
-  final _value;
-
-  const _ContainsValue(this._value);
-
-  bool matches(item, Map matchState) => item.containsValue(_value);
-  Description describe(Description description) =>
-      description.add('contains value ').addDescriptionOf(_value);
-}
-
-/// Returns a matcher which matches maps containing the key-value pair
-/// with [key] => [value].
-Matcher containsPair(key, value) =>
-    new _ContainsMapping(key, wrapMatcher(value));
-
-class _ContainsMapping extends Matcher {
-  final _key;
-  final Matcher _valueMatcher;
-
-  const _ContainsMapping(this._key, Matcher this._valueMatcher);
-
-  bool matches(item, Map matchState) =>
-      item.containsKey(_key) && _valueMatcher.matches(item[_key], matchState);
-
-  Description describe(Description description) {
-    return description
-        .add('contains pair ')
-        .addDescriptionOf(_key)
-        .add(' => ')
-        .addDescriptionOf(_valueMatcher);
-  }
-
-  Description describeMismatch(
-      item, Description mismatchDescription, Map matchState, bool verbose) {
-    if (!item.containsKey(_key)) {
-      return mismatchDescription
-          .add(" doesn't contain key ")
-          .addDescriptionOf(_key);
-    } else {
-      mismatchDescription
-          .add(' contains key ')
-          .addDescriptionOf(_key)
-          .add(' but with value ');
-      _valueMatcher.describeMismatch(
-          item[_key], mismatchDescription, matchState, verbose);
-      return mismatchDescription;
-    }
-  }
-}