Mock the window.setTimeout in a Jasmine test to avoid waiting
- by Aligned
Originally posted on: http://geekswithblogs.net/Aligned/archive/2014/08/21/mock-the-window.settimeout-in-a-jasmine-test-to-avoid-waiting.aspxJasmine has a clock mocking feature, but I was unable to make it work in a function that I’m calling and want to test. The example only shows using clock for a setTimeout in the spec tests and I couldn’t find a good example. Here is my current and slightly limited approach. If we have a method we want to test: var test = function(){
var self = this;
self.timeoutWasCalled = false;
self.testWithTimeout = function(){
window.setTimeout(function(){
self.timeoutWasCalled = true;
}, 6000);
};
};
Here’s my testing code:
var realWindowSetTimeout = window.setTimeout;
describe('test a method that uses setTimeout', function(){
var testObject;
beforeEach(function () {
// force setTimeout to be called right away, no matter what time they specify
jasmine.getGlobal().setTimeout = function (funcToCall, millis) {
funcToCall();
};
testObject = new test();
});
afterEach(function() {
jasmine.getGlobal().setTimeout = realWindowSetTimeout;
});
it('should call the method right away', function(){
testObject.testWithTimeout();
expect(testObject.timeoutWasCalled).toBeTruthy();
});
});
I got a good pointer from Andreas in this StackOverflow question.
This would also work for window.setInterval.
Other possible approaches:
create a wrapper module of setTimeout and setInterval methods that can be mocked. This can be mocked with RequireJS or passed into the constructor.
pass the window.setTimeout function into the method (this could get messy)
