Added hasProperty matcher.

pkg/unittest/lib/src/core_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.
 
 part of matcher;
 
 /**
  * Returns a matcher that matches empty strings, maps or iterables
  * (including collections).
  */
@@ skipping 831 matching lines @@
  * A useful utility class for implementing other matchers through inheritance.
  * Derived classes should call the base constructor with a feature name and
  * description, and an instance matcher, and should implement the
  * [featureValueOf] abstract method.
  *
  * The feature description will typically describe the item and the feature,
  * while the feature name will just name the feature. For example, we may
  * have a Widget class where each Widget has a price; we could make a
  * [CustomMatcher] that can make assertions about prices with:
  *
-<<<<<<< .mine
  *     class HasPrice extends CustomMatcher {
  *       const HasPrice(matcher) :
-=======
- *     class HasPrice extends CustomMatcher {
- *       HasPrice(matcher) :
->>>>>>> .r25321
  *           super("Widget with price that is", "price", matcher);
  *       featureValueOf(actual) => actual.price;
  *     }
  *
  * and then use this for example like:
  *
  *      expect(inventoryItem, new HasPrice(greaterThan(0)));
  */
 class CustomMatcher extends Matcher {
   final String _featureDescription;
@@ skipping 23 matching lines @@
     var innerDescription = new StringDescription();
     _matcher.describeMismatch(matchState['feature'], innerDescription,
         matchState['state'], verbose);
     if (innerDescription.length > 0) {
       mismatchDescription.add(' which ').add(innerDescription.toString());
     }
     return mismatchDescription;
   }
 }
 
+/**
+ * Returns a matcher that checks if a class instance has a property
+ * with name [name], and optionally, if that property in turn satisfies
+ * a [matcher].
+ */
+Matcher hasProperty(String name, [matcher]) =>
+  new _HasProperty(name, matcher == null ? null : wrapMatcher(matcher));
+
+class _HasProperty extends Matcher {
+  final String _name;
+  final Matcher _matcher;
+
+  const _HasProperty(this._name, [this._matcher]);
+
+  bool matches(item, Map matchState) {
+    if (item is! Object) {
+      addStateInfo(matchState, {'reason': 'Not an object'});
+      return false;
+    }
+    var mirror = reflect(item);
+    var classMirror = mirror.type;
+    var symbol = new Symbol(_name);
+    if (!classMirror.getters.containsKey(symbol)) {
+      addStateInfo(matchState, {'reason': 'No property named $_name'});
+      return false;
+    }
+    if (_matcher == null) return true;
+    var result = mirror.getField(symbol);
+    var resultMatches = _matcher.matches(result.reflectee, matchState);
+    if (!resultMatches) {
+      addStateInfo(matchState, {'value': result.reflectee});
+    }
+    return resultMatches;
+  }
+
+  Description describe(Description description) {
+    description.add('has property $_name');

[Siggi Cherem (dart-lang), 2013/07/31 00:23:30]

might be good to quote the name "$_name"

+    if (_matcher != null) {
+      description.add(' which matches ').addDescriptionOf(_matcher);
+    }
+    return description;
+  }
+
+  Description describeMismatch(item, Description mismatchDescription,
+                               Map matchState, bool verbose) {
+    var reason = matchState == null ? null : matchState['reason'];
+    if (reason != null) {
+      mismatchDescription.add(reason);
+    } else {
+      mismatchDescription.add('has property $_name with value ').

[Siggi Cherem (dart-lang), 2013/07/31 00:23:30]

same here, so it reads:
has property "length" with value ___

+        addDescriptionOf(matchState['value']);
+      var innerDescription = new StringDescription();
+      _matcher.describeMismatch(matchState['value'], innerDescription,
+          matchState['state'], verbose);
+      if (innerDescription.length > 0) {
+        mismatchDescription.add(' which ').add(innerDescription.toString());
+      }
+    }
+    return mismatchDescription;
+  }
+}
+