Using object types with Jasmine's toHaveBeenCalledWith method

Question

I've just started using Jasmine so please forgive the newbie question but is it possible to test for object types when using toHaveBeenCalledWith?

expect(object.method).toHaveBeenCalledWith(instanceof String);

I know I could this but it's checking the return value rather than the argument.

expect(k instanceof namespace.Klass).toBeTruthy();

score 124 · Answer 1 · edited Feb 18 '15 at 23:47

124

I've discovered an even cooler mechanism, using jasmine.any(), as I find taking the arguments apart by hand to be sub-optimal for legibility.

In CoffeeScript:

obj = {}
obj.method = (arg1, arg2) ->

describe "callback", ->

   it "should be called with 'world' as second argument", ->
     spyOn(obj, 'method')
     obj.method('hello', 'world')
     expect(obj.method).toHaveBeenCalledWith(jasmine.any(String), 'world')

edited Feb 18 '15 at 23:47

Mark Amery

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answered Feb 02 '12 at 00:39

Wolfram Arnold

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jasmine.any(Function) is handy, too – stefan.s Apr 12 '12 at 10:01
2

Noticed that it also works inside on references. for example: `expect(obj.method).toHaveBeenCalledWith({done: jasmine.any(Function)})`. Very useful. – fncomp Jan 21 '15 at 09:19
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As of the time of this writing, Jasmine does not check for the same instance of `new String('world')` when using `toHaveBeenCalledWith(...arguments)`. [Click here](https://medium.com/@fagnerbrack/mocking-can-lean-to-nondeterministic-tests-4ba8aef977a0) to understand why that is important. – Fagner Brack Jun 30 '16 at 05:54
1

Had to check if a callback function was called, `jasmin.any(Function)` saved my life, thank you – Jul 07 '17 at 09:47

score 58 · Accepted Answer · edited Jun 11 '19 at 10:05

58

toHaveBeenCalledWith is a method of a spy. So you can only call them on spy like described in the docs:

// your class to test
var Klass = function () {
};

Klass.prototype.method = function (arg) {
  return arg;
};


//the test
describe("spy behavior", function() {

  it('should spy on an instance method of a Klass', function() {
    // create a new instance
    var obj = new Klass();
    //spy on the method
    spyOn(obj, 'method');
    //call the method with some arguments
    obj.method('foo argument');
    //test the method was called with the arguments
    expect(obj.method).toHaveBeenCalledWith('foo argument');   
    //test that the instance of the last called argument is string 
    expect(obj.method.calls.mostRecent().args[0] instanceof String).toBeTruthy();
  });

});

edited Jun 11 '19 at 10:05

Roger C S Wernersson

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answered Jan 10 '12 at 12:00

Andreas Köberle

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Andreas, is there any reason you added `.toBeTruthy()`? It seems like that is unnecessary. – jds Sep 23 '13 at 15:38
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@gwg `expect(foo)` without a matcher is a no-op; the line would do nothing without the `toBeTruthy()` call. See http://jsfiddle.net/2doafezv/2/ for proof. – Mark Amery Feb 18 '15 at 23:42
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This is out of date; `obj.method.mostRecentCall` needs to become [`obj.method.calls.mostRecent()`](http://jasmine.github.io/2.0/introduction.html#section-Other_tracking_properties) in Jasmine 2.0. Also, using `jasmine.any()`, as described in the other answer, is clearer and cuter. Finally, this answer takes a while to get to the point; essentially everything you wrote besides `expect(obj.method.mostRecentCall.args[0] instanceof String).toBeTruthy();` isn't really needed to explain yourself. – Mark Amery Feb 18 '15 at 23:54

Using object types with Jasmine's toHaveBeenCalledWith method

2 Answers2