Mock the window.setTimeout in a Jasmine test to avoid waiting
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by Aligned
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Published on Thu, 21 Aug 2014 06:32:06 GMT
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2014/08/21
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Originally posted on: http://geekswithblogs.net/Aligned/archive/2014/08/21/mock-the-window.settimeout-in-a-jasmine-test-to-avoid-waiting.aspx
Jasmine 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)
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