处理Jasmine测试中的javascript错误

Question

I'm developing a javascript application which listens to window.onerror() and reports to an endpoint me and my team are building. I'm this using grunt-contrib-jasmine for the unit test side of things and am running into issues since my test cases expect errors to be thrown.

When running test cases with phantom, this clutters up my output unnecessarily: http://cl.ly/image/1n3k3z2g2V2l

In the instance of the reference error, my test looks like this:

it("should report reference errors", function() {
    spyOn(window.fred, 'sendRequest').andCallFake(function(details) {
        expect(details.type).toEqual('js-error');
        expect(details.message).toBeNonEmptyString();
    });
    runs(function() {
        var script = document.createElement('script');
        script.type = 'text/javascript';
        script.innerHTML = 'reference_error;';
        document.body.appendChild(script);
    });

    waits(2000);

    runs(function() {
        expect(window.fred.sendRequest).toHaveBeenCalled();
    });
});

I want to be able to handle the ReferenceError which gets thrown at some point in the code. As best I can see, this happens indirectly at document.body.appendChild(script); . Jasmine's expect(fn).toThrow(e) looks like it would do the job if I used it here however the test still fails. I've also tried surround it with a try { ... } catch (err) { ... } but to no avail.

My question, does anyone have any suggestions on how to deal with this?

Answer 1

Normally jasmine will try to catch any exceptions that are thrown by your specs and have those mark the spec as failed. However, because this exception is being thrown by the browser when it tries to parse your script tag, jasmine isn't in the call stack. This is why toThrow doesn't work.

Also, as long as your onerror method returns true the browser should not do it's default error action , in this case log to the console.