feat(ngMock, ngMockE2E): add option to match latest definition for $httpBackend request

Closes #16251
Closes #11637
Closes #16560

Author: Narretz

src/ngMock/angular-mocks.js

@@ -1342,6 +1342,7 @@ angular.mock.$httpBackendDecorator =
 function createHttpBackendMock($rootScope, $timeout, $delegate, $browser) {
   var definitions = [],
       expectations = [],
+      matchLatestDefinition = false,
       responses = [],
       responsesPush = angular.bind(responses, responses.push),
       copy = angular.copy,
@@ -1430,8 +1431,9 @@ function createHttpBackendMock($rootScope, $timeout, $delegate, $browser) {
       wasExpected = true;
     }
 
-    var i = -1, definition;
-    while ((definition = definitions[++i])) {
+    var i = matchLatestDefinition ? definitions.length : -1, definition;
+
+    while ((definition = definitions[matchLatestDefinition ? --i : ++i])) {
       if (definition.match(method, url, data, headers || {})) {
         if (definition.response) {
           // if $browser specified, we do auto flush all requests
@@ -1507,6 +1509,47 @@ function createHttpBackendMock($rootScope, $timeout, $delegate, $browser) {
     return chain;
   };
 
+  /**
+   * @ngdoc method
+   * @name  $httpBackend#matchLatestDefinition
+   * @description
+   * This method can be used to change which mocked responses `$httpBackend` returns, when defining
+   * them with {@link ngMock.$httpBackend#when $httpBackend.when()} (and shortcut methods).
+   * By default, `$httpBackend` returns the first definition that matches. When setting
+   * `$http.matchLatestDefinition(true)`, it will use the last response that matches, i.e. the
+   * one that was added last.
+   *
+   * ```js
+   * hb.when('GET', '/url1').respond(200, 'content', {});
+   * hb.when('GET', '/url1').respond(201, 'another', {});
+   * hb('GET', '/url1'); // receives "content"
+   *
+   * $http.matchLatestDefinition(true)
+   * hb('GET', '/url1'); // receives "another"
+   *
+   * hb.when('GET', '/url1').respond(201, 'onemore', {});
+   * hb('GET', '/url1'); // receives "onemore"
+   * ```
+   *
+   * This is useful if a you have a default response that is overriden inside specific tests.
+   *
+   * Note that different from config methods on providers, `matchLatestDefinition()` can be changed
+   * even when the application is already running.
+   *
+   * @param  {Boolean=} value value to set, either `true` or `false`. Default is `false`.
+   *                          If omitted, it will return the current value.
+   * @return {$httpBackend|Boolean} self when used as a setter, and the current value when used
+   *                                as a getter
+   */
+  $httpBackend.matchLatestDefinitionEnabled = function(value) {
+    if (isDefined(value)) {
+      matchLatestDefinition = value;
+      return this;
+    } else {
+      return matchLatestDefinition;
+    }
+  };
+
   /**
    * @ngdoc method
    * @name $httpBackend#whenGET

test/ngMock/angular-mocksSpec.js

@@ -1090,7 +1090,7 @@ describe('ngMock', function() {
     });
 
 
-    it('should respond with first matched definition', function() {
+    it('should respond with first matched definition by default', function() {
       hb.when('GET', '/url1').respond(200, 'content', {});
       hb.when('GET', '/url1').respond(201, 'another', {});
 
@@ -1106,6 +1106,78 @@ describe('ngMock', function() {
     });
 
 
+    describe('matchLatestDefinitionEnabled()', function() {
+
+      it('should be set to false by default', function() {
+        expect(hb.matchLatestDefinitionEnabled()).toBe(false);
+      });
+
+
+      it('should allow to change the value', function() {
+        hb.matchLatestDefinitionEnabled(true);
+        expect(hb.matchLatestDefinitionEnabled()).toBe(true);
+      });
+
+
+      it('should return the httpBackend when used as a setter', function() {
+        expect(hb.matchLatestDefinitionEnabled(true)).toBe(hb);
+      });
+
+
+      it('should respond with the first matched definition when false',
+        function() {
+          hb.matchLatestDefinitionEnabled(false);
+
+          hb.when('GET', '/url1').respond(200, 'content', {});
+          hb.when('GET', '/url1').respond(201, 'another', {});
+
+          callback.and.callFake(function(status, response) {
+            expect(status).toBe(200);
+            expect(response).toBe('content');
+          });
+
+          hb('GET', '/url1', null, callback);
+          expect(callback).not.toHaveBeenCalled();
+          hb.flush();
+          expect(callback).toHaveBeenCalledOnce();
+        }
+      );
+
+
+      it('should respond with latest matched definition when true',
+        function() {
+          hb.matchLatestDefinitionEnabled(true);
+
+          hb.when('GET', '/url1').respond(200, 'match1', {});
+          hb.when('GET', '/url1').respond(200, 'match2', {});
+          hb.when('GET', '/url2').respond(204, 'nomatch', {});
+
+          callback.and.callFake(function(status, response) {
+            expect(status).toBe(200);
+            expect(response).toBe('match2');
+          });
+
+          hb('GET', '/url1', null, callback);
+
+          // Check if a newly added match is used
+          hb.when('GET', '/url1').respond(201, 'match3', {});
+
+          var callback2 = jasmine.createSpy();
+
+          callback2.and.callFake(function(status, response) {
+            expect(status).toBe(201);
+            expect(response).toBe('match3');
+          });
+
+          hb('GET', '/url1', null, callback2);
+          expect(callback).not.toHaveBeenCalled();
+          hb.flush();
+          expect(callback).toHaveBeenCalledOnce();
+        }
+      );
+    });
+
+
     it('should respond with a copy of the mock data', function() {
       var mockObject = {a: 'b'};