fix(angular-mocks): use copy of mock data in $httpBackend

Copy mock data returned from the mock $httpBackend.
This prevents modifications to the response from affecting future responses.
Previously, this misbehavior was being mitigated by the deep copy in $resource, but that no longer exists.

src/ngMock/angular-mocks.js

@@ -1087,7 +1087,8 @@ function createHttpBackendMock($rootScope, $delegate, $browser) {
   var definitions = [],
       expectations = [],
       responses = [],
-      responsesPush = angular.bind(responses, responses.push);
+      responsesPush = angular.bind(responses, responses.push),
+      copy = angular.copy;
 
   function createResponse(status, data, headers) {
     if (angular.isFunction(status)) return status;
@@ -1119,7 +1120,7 @@ function createHttpBackendMock($rootScope, $delegate, $browser) {
       function handleResponse() {
         var response = wrapped.response(method, url, data, headers);
         xhr.$$respHeaders = response[2];
-        callback(response[0], response[1], xhr.getAllResponseHeaders());
+        callback(copy(response[0]), copy(response[1]), xhr.getAllResponseHeaders());
       }
 
       function handleTimeout() {

test/ngMock/angular-mocksSpec.js

@@ -766,7 +766,7 @@ describe('ngMock', function() {
 
       describe('object literal format', function() {
         var mock = { log: 'module' };
-        
+
         beforeEach(function() {
           module({
               'service': mock,
@@ -782,7 +782,7 @@ describe('ngMock', function() {
             expect(service).toEqual(mock);
           });
         });
-        
+
         it('should support multiple key value pairs', function() {
           inject(function(service, other) {
             expect(other.some).toEqual('replacement');
@@ -891,6 +891,32 @@ describe('ngMock', function() {
     });
 
 
+    it('should respond with a copy of the mock data', function() {
+      var mockObject = {a: 'b'};
+
+      hb.when('GET', '/url1').respond(200, mockObject, {});
+
+      callback.andCallFake(function(status, response) {
+        expect(status).toBe(200);
+        expect(response).toEqual({a: 'b'});
+        expect(response).not.toBe(mockObject);
+        response.a = 'c';
+      });
+
+      hb('GET', '/url1', null, callback);
+      hb.flush();
+      expect(callback).toHaveBeenCalledOnce();
+
+      // Fire it again and verify that the returned mock data has not been
+      // modified.
+      callback.reset();
+      hb('GET', '/url1', null, callback);
+      hb.flush();
+      expect(callback).toHaveBeenCalledOnce();
+      expect(mockObject).toEqual({a: 'b'});
+    });
+
+
     it('should throw error when unexpected request', function() {
       hb.when('GET', '/url1').respond(200, 'content');
       expect(function() {