How to have different return values for multiple calls on a Jasmine spy

javascript unit-testing jasmine
mikhail picture mikhail · Nov 13, 2014 · Viewed 55.8k times · Source

Say I'm spying on a method like this:

spyOn(util, "foo").andReturn(true);

The function under test calls util.foo multiple times.

Is it possible to have the spy return true the first time it's called, but return false the second time? Or is there a different way to go about this?

Answer

Ocean picture Ocean · Feb 1, 2016

You can use spy.and.returnValues (as Jasmine 2.4).

for example

describe("A spy, when configured to fake a series of return values", function() {
  beforeEach(function() {
    spyOn(util, "foo").and.returnValues(true, false);
  });

  it("when called multiple times returns the requested values in order", function() {
    expect(util.foo()).toBeTruthy();
    expect(util.foo()).toBeFalsy();
    expect(util.foo()).toBeUndefined();
  });
});

There is some thing you must be careful about, there is another function will similar spell returnValue without s, if you use that, jasmine will not warn you.

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