Check for ObjectContaining on either side of equality.

- Also clean up `undefined` check.

Fixes #682

spec/core/ObjectContainingSpec.js

@@ -43,4 +43,16 @@ describe("ObjectContaining", function() {
 
     expect(containing.asymmetricMatch({one: {two: {}}})).toBe(true);
   });
+
+  it("matches when key is present with undefined value", function() {
+    var containing = new j$.ObjectContaining({ one: undefined });
+
+    expect(containing.asymmetricMatch({ one: undefined })).toBe(true);
+  });
+
+  it("does not match when key with undefined value is not present", function() {
+    var containing = new j$.ObjectContaining({ one: undefined });
+
+    expect(containing.asymmetricMatch({})).toBe(false);
+  });
 });

spec/core/matchers/matchersUtilSpec.js

@@ -191,9 +191,11 @@ describe("matchersUtil", function() {
       var obj = {
         foo: 3,
         bar: 7
-      };
+      },
+      containing = new j$.ObjectContaining({foo: 3});
 
-      expect(j$.matchersUtil.equals(obj, new j$.ObjectContaining({foo: 3}))).toBe(true);
+      expect(j$.matchersUtil.equals(obj, containing)).toBe(true);
+      expect(j$.matchersUtil.equals(containing, obj)).toBe(true);
     });
 
     it("passes when a custom equality matcher returns true", function() {