feat(TzDate): add mock "toString" method to TzDate.

- If the third param of TzDate constructor is defined, toStirng will
just return this third parameter. Otherwise, toString will still
be treated as unimplemented method

src/angular-mocks.js

@@ -457,7 +457,7 @@ function MockLogFactory() {
  * </pre>
  *
  */
-function TzDate(offset, timestamp) {
+function TzDate(offset, timestamp, toStringVal) {
   if (angular.isString(timestamp)) {
     var tsStr = timestamp;
 
@@ -481,6 +481,10 @@ function TzDate(offset, timestamp) {
     return this.date.getTime() - this.offsetDiff;
   };
 
+  this.toString = function() {
+   return toStringVal;
+  }
+
   this.toLocaleDateString = function() {
     return this.date.toLocaleDateString();
   };
@@ -551,6 +555,8 @@ function TzDate(offset, timestamp) {
       'toLocaleTimeString', 'toSource', 'toString', 'toTimeString', 'toUTCString', 'valueOf'];
 
   angular.forEach(unimplementedMethods, function(methodName) {
+    if (methodName == 'toString' && toStringVal) return;
+
     self[methodName] = function() {
       throw {
         name: "MethodNotImplemented",

test/angular-mocksSpec.js

@@ -121,6 +121,22 @@ describe('mocks', function(){
       expect(date2.getUTCMinutes()).toBe(0);
       expect(date2.getUTCSeconds()).toBe(0);
     });
+
+
+    it('should fake toString method when a third param is passed in', function() {
+      var t = new TzDate(0, 0, 'Mon Sep 3 2010 17:05:08 GMT+0500 (XYZ)');
+      expect(t.toString()).toBe('Mon Sep 3 2010 17:05:08 GMT+0500 (XYZ)');
+    });
+
+
+    it('should throw error when no third param but toString called', function() {
+      var t = new TzDate(0, 0);
+      try {
+        t.toString();
+       } catch(err) {
+         expect(err.name).toBe('MethodNotImplemented');
+       }
+    })
   });
 
   describe('$log mock', function() {