javascript - How to use spyOn to mock jQuery value for a selector in Jasmine? -

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• spying on jquery selectors in jasmine 6 answers

i'm writing unit tests using angularjs / karma / jasmine , couldn't jasmine's 'spyon' method work. after use spyon, i'm still getting undefined selector.

the problem

the issue i'm running into, after run

spyon($("#username"), "val").and.returnvalue("test@test.com"); 

i try value of username this:

$("#username").val(); 

and undefined.

code want test

function isvalidemail() {        var email = $("#username").val();        var regex = /^([a-za-z0-9_.+-])+\@(([a-za-z0-9-])+\.)+([a-za-z0-9]{2,4})+$/;        return email.match(regex);  } 

unit test

'use strict';  describe('test/spec/controllers/validation.js - no controller', function () {  describe('email validation', function () {      it('should true valid emails', function() {           spyon($("#username"), "val").and.returnvalue("test@test.com");          var result = isvalidemail();          expect(result).toequal(true);      }); });  }); 

anyone see did wrong?

your problem each time call $("#username"), different object. therefore, $("#username") in function not spied on.

you should instead spy on $.fn, shared jquery objects.

spyon($.fn, 'val').and.returnvalue('test@test.com')