Jasmine spyOn javascript getter causing karma to hang

问题

I'm having some issues using Jasmine to write tests which spy on a Javascript getter. It causes my test suite to hang (using karma + phantomJS) and then ultimately the browser disconnects having never progressed further than the test in question.

A simple example is probably the easiest way to explain (using ES6 transpiled with webpack + babel-loader):

class ExampleClass {
    get name() {
        return "My Name";
    }
}

In order to change what this get method returns for my test, I am trying the following:

describe("example class getter"), function() {
    it("should return blue", function() {
        let exampleClass = new ExampleClass();
        spyOn(exampleClass, 'name').and.returnValue('blue');
        expect(exampleClass.name).toBe('blue');
    });
});

This results in the following (where the test in question is my 7th test):

PhantomJS 1.9.8 (Mac OS X 0.0.0): Executed 6 of 8 SUCCESS (0 secs / 0.02 secs)
WARN [PhantomJS 1.9.8 (Mac OS X 0.0.0)]: Disconnected (1 times), because no message in 10000 ms.
PhantomJS 1.9.8 (Mac OS X 0.0.0): Executed 6 of 8 DISCONNECTED (10.003 secs / 0.02 secs)
DEBUG [karma]: Run complete, exiting.

spyOn is working for other methods which aren't defined using the get syntax, so I am confident the build pipeline for transpilation is working fine.

Has anyone seen this before, or have any ideas about a fix?

回答1:

I've got the same. Here's the way I've solved this:

class Foo {
  get status() {
    return 0;
  }
}

So mock this Foo for test:

class FooMock extends Foo {
  _fakeStatus() {
    return 1;
  }

  get status() {
    return this._fakeStatus();
  }
}

And then you use the FooMock instead the Foo! e.g:

it('check the status', () => {
  spyOn(fooInstance, '_fakeStatus').and.returnValue(3);
  expect(fooInstance.status).toBe(3);
}

Hope this works for you! :)

回答2:

I think you neglected to invoke the name function in your expect call. Like this:

describe("example class getter"), function() {
    it("should return blue", function() {
        let exampleClass = new ExampleClass();
        spyOn(exampleClass, 'name').and.returnValue('blue');
        expect(exampleClass.name()).toBe('blue');
    });
});

来源：https://stackoverflow.com/questions/31338197/jasmine-spyon-javascript-getter-causing-karma-to-hang

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javascript

jasmine

ecmascript-6