test(privateMocks): allow replacing $prop with strings with special RegExp semantics

`baseThey` used to construct the testcase description by replacing `$prop` using a RegExp.
If the replacement string contained `$&` (which has a special meaning with RegExps), the resulting
string was not as expected.x

Author: gkalpak

test/helpers/privateMocks.js

@@ -11,7 +11,7 @@ function baseThey(msg, vals, spec, itFn) {
   var valsIsArray = angular.isArray(vals);
 
   angular.forEach(vals, function(val, key) {
-    var m = msg.replace(/\$prop/g, angular.toJson(valsIsArray ? val : key));
+    var m = msg.split('$prop').join(angular.toJson(valsIsArray ? val : key));
     itFn(m, function() {
       /* jshint -W040 : ignore possible strict violation due to use of this */
       spec.call(this, val);

test/helpers/privateMocksSpec.js

@@ -22,6 +22,13 @@ describe('private mocks', function() {
         expect(window.it).toHaveBeenCalledWith('should fight "fire" with "fire"', jasmine.any(Function));
       });
 
+      it('should handle replacement strings containing `$&` correctly', function() {
+        spyOn(window, 'it');
+
+        they('should replace dollar-prop with $prop', ['$&']);
+        expect(window.it).toHaveBeenCalledWith('should replace dollar-prop with "$&"', jasmine.any(Function));
+      });
+
       it('should pass each item in an array to the handler', function() {
         var handlerSpy = jasmine.createSpy('handler');
         spyOn(window, 'it').andCallFake(function(msg, handler) {