I am currently writing some tests in a legacy system and am confused about a test result here.
I have one test here which fails as expected but mocha shows as a result 1 passing and 1 failing.
I am using Bluebird Promises, mocha, chai-as-promised and sinon with sinon-chai for spies and stubs. This is the test (I have removed stuff not needed for understanding my problem):
describe("with a triggerable activity (selection)", function () {
beforeEach(function stubData() {
stubbedTriggerFunction = sinon.stub(trigger, "newParticipation");
activityLibStub = ... // stub
selectionLibStub = ... // stub
fakeActivities = ... // simple data with just ONE element
fakeSelection = ... // simple data with just ONE element
// stub methods to return synthetic data
activityLibStub.returns(new Promise(function (resolve) {
resolve(fakeActivities);
}));
selectionLibStub.withArgs(1).returns(new Promise(function (resolve) {
resolve(fakeSelection);
}));
});
afterEach(function releaseStubs() {
// restore stubs...
});
it("should call the newParticipation function", function () {
var member = memberBuilder.buildCorrect();
trigger.allActivities(member)
.then(function () {
return expect(stubbedTriggerFunction).to.not.have.been.called;
})
.done();
})
});
This test fails as expected, because the function is actually invoked. However, mocha tells me that one test passed and one test failed. This is the only test I have implemented in this module.
I am pretty sure this has something to do with the promises but I don't seem to figure out what it is. Also if I add
.catch(function(){
chai.assert.fail();
})
after the then-block, mocha still claims that one test passed. The method is also just invoked one time and I have only one synthetic dataset which I am working with. So I don't see what it is which tells mocha that this has passed while failed...
Any ideas?
Regards, Vegaaaa
Return your promise, return your promise, return your promise. Let's chant it all together now "Return, yoooooooour promise!"
it("should call the newParticipation function", function () {
var member = memberBuilder.buildCorrect();
return trigger.allActivities(member)
.then(function () {
return expect(stubbedTriggerFunction).to.not.have.been.called;
});
})
});
I've also removed .done() because that's not generally useful with Bluebird and would be downright harmful here. Mocha still needs to use your promise.
(It's use is generally discouraged, see here.) If you do not return your promise, then Mocha treats you test as synchronous and most likely that's going to be successful because your test is not really testing anything synchronously. Then if you get an asychronous failure, Mocha has to decide what failed exactly and will do its best to record the failure but it can lead to funny things like having an incorrect number of tests or the same test being reported as failed and successful!
Related
In my journey towards TDD, I am using Mocha, chai and sinon.
There certainly is a learning curve there.
My goal is to write a test to verify that method4 was executed. How do I achieve that ?
//MyData.js
class MyData {
constructor(input) {
this._runMethod4 = input; //true or false
this.underProcessing = this.init();
}
method1() { return this.method2() }
method2() {
if (this._runMethod4) {
return this.method4();
} else {
return this.method3();
}
method4(){
return thirdPartyAPI.getData();
}
method3(){
return someAPI.fetchData();
}
init(){
return this.method1();
}
}
MyData.spec.js
describe('MyData', () => {
it('should execute method 4', function() {
let foo = new MyData(true);
foo.underProcessing.then(()=>{
// How do I verify that method4 was executed ??
expect(foo.method4.callCount).to.equal(1);
});
});
})
Here's an example:
const expect = require('chai').expect;
const sinon = require('sinon');
const sinonTest = require('sinon-test');
sinon.test = sinonTest.configureTest(sinon);
sinon.testCase = sinonTest.configureTestCase(sinon);
describe("MyData", () => {
it("should execute method 4", sinon.test(function() {
let spy = this.spy(MyData.prototype, 'method4');
let foo = new MyData(true);
return foo.underProcessing.then(() => {
expect(spy.callCount).to.equal(1);
});
}));
});
As an additional requirement, I added sinon-test because it's really useful to help clean up spies/stubs after the test has run.
The main feature is this line:
let spy = this.spy(MyData.prototype, 'method4');
This replaces MyData.prototype.method4 by a Sinon spy, which is a pass-through function (so it calls the original) that will record how exactly it was called, how often, with what arguments, etc. You need to do this before the instance is created, because otherwise you're too late (the method might already have been called through the chain of method calls that starts with this.init() in the constructor).
If you want to use a stub instead, which is not pass-through (so it won't call the original method), you can do that as well:
let spy = this.stub(MyData.prototype, 'method4').returns(Promise.resolve('yay'));
So instead of calling thirdPartyAPI.getData() and returning its result, method4 will now return a promise resolved with the value yay.
The remaining code should speak for itself, with one caveat: an explicit return in front of foo.underProcessing.then(...).
I assume that foo.underProcessing is a promise, so it's asynchronous, which means that your test should be asynchronous as well. Since Mocha supports promises, when you return a promise from a test, Mocha will know how to deal with it properly (there's an alternative method of making an asynchronous test with Mocha, involving callback functions, but when you're testing promise-based code you shouldn't really use those since it's easy to run into timeouts or swallowed exceptions).
I must be doing something wrong, however this is my testcase:
const { describe, it } = require('mocha'),
should = require('should'),
Promise = require('bluebird') //v3.4.6
describe('Bluebird', () => {
it('Promise is never resolved but does it get resolved?', () => {
new Promise(() => false)
.should.be.fulfilled() // It really shouldn't be
})
})
This passes, but shouldn't it fail?
When working with promises in mocha tests, it is important to return the promise from the test.
In your case, that would be:
it('Promise is never resolved but does it get resolved?', () => {
return new Promise(() => false)
.should.be.fulfilled()
})
However, that is probably still not exactly what you need here, as the fulfillment of the promise can't be determined at the time should is invoked. Your actual test is probably different, the most important part is still to return the promise chain.
When you do that, then you don't need to further assert the fulfillment/rejection of the promise, as that is done implicitly by mocha.
I'm personally a big fan of chai-as-promised, which would allow you to use the exact same test you had before, but this time, it would be working.
I am experimenting with Promise from ES6, but I can't find any alternative to complete as in jQuery ajax. I need to execute function after all the registered handlers with "then".
Thanks!
As mentioned by Bergi, what you want is the disposer pattern. Your central conception of a promise appears to be a bit off, and I think that is making this harder for you to reason about. When you call .then, you are not conceptually "attaching a handler", you are creating a new promise that will by definition resolve after all of its .then handlers have run.
Given your central issue based on code like this:
// a.js
module.exports = function(){
// Where 'Promise.resolve()' is a stand in for your ajax.
return Promise.resolve()
.then(function(){
// Want this to run after 'B'.
});
}
// b.js
var makePromise = require('./a');
module.exports = function specialMakePromise(){
return makePromise().then(function(){
// Should run first.
});
}
They will always run in the wrong order, because by definition, the .then handler from a.js must run and complete before the .then handler from b.js.
One way to approach this problem would instead to structure your code like this:
// a.js
module.exports = function(callback){
return Promise.resolve()
.then(callback)
.then(function(){
// Want this to run after 'B'.
});
}
// b.js
var makePromise = require('./a');
module.exports = function specialMakePromise(){
return makePromise(function(){
// Should run first.
});
}
I have some tests that fail in PhantomJS but not other browsers.
I'd like these tests to be ignored when run with PhantomJS in my watch task (so new browser windows don't take focus and perf is a bit faster), but in my standard test task and my CI pipeline, I want all the tests to run in Chrome, Firefox, etc...
I've considered a file-naming convention like foo.spec.dont-use-phantom.js and excluding those in my Karma config, but this means that I will have to separate out the individual tests that are failing into their own files, separating them from their logical describe blocks and having more files with weird naming conventions would generally suck.
In short:
Is there a way I can extend Jasmine and/or Karma and somehow annotate individual tests to only run with certain configurations?
Jasmine supports a pending() function.
If you call pending() anywhere in the spec body, no matter the expectations, the spec will be marked pending.
You can call pending() directly in test, or in some other function called from test.
function skipIfCondition() {
pending();
}
function someSkipCheck() {
return true;
}
describe("test", function() {
it("call pending directly by condition", function() {
if (someSkipCheck()) {
pending();
}
expect(1).toBe(2);
});
it("call conditionally skip function", function() {
skipIfCondition();
expect(1).toBe(3);
});
it("is executed", function() {
expect(1).toBe(1);
});
});
working example here: http://plnkr.co/edit/JZtAKALK9wi5PdIkbw8r?p=preview
I think it is purest solution. In test results you can see count of finished and skipped tests.
The most simple solution that I see is to override global functions describe and it to make them accept third optional argument, which has to be a boolean or a function returning a boolean - to tell whether or not current suite/spec should be executed. When overriding we should check if this third optional arguments resolves to true, and if it does, then we call xdescribe/xit (or ddescribe/iit depending on Jasmine version), which are Jasmine's methods to skip suite/spec, istead of original describe/it. This block has to be executed before the tests, but after Jasmine is included to the page. In Karma just move this code to a file and include it before test files in karma.conf.js. Here is the code:
(function (global) {
// save references to original methods
var _super = {
describe: global.describe,
it: global.it
};
// override, take third optional "disable"
global.describe = function (name, fn, disable) {
var disabled = disable;
if (typeof disable === 'function') {
disabled = disable();
}
// if should be disabled - call "xdescribe" (or "ddescribe")
if (disable) {
return global.xdescribe.apply(this, arguments);
}
// otherwise call original "describe"
return _super.describe.apply(this, arguments);
};
// override, take third optional "disable"
global.it = function (name, fn, disable) {
var disabled = disable;
if (typeof disable === 'function') {
disabled = disable();
}
// if should be disabled - call "xit" (or "iit")
if (disable) {
return global.xit.apply(this, arguments);
}
// otherwise call original "it"
return _super.it.apply(this, arguments);
};
}(window));
And usage example:
describe('foo', function () {
it('should foo 1 ', function () {
expect(true).toBe(true);
});
it('should foo 2', function () {
expect(true).toBe(true);
});
}, true); // disable suite
describe('bar', function () {
it('should bar 1 ', function () {
expect(true).toBe(true);
});
it('should bar 2', function () {
expect(true).toBe(true);
}, function () {
return true; // disable spec
});
});
See a working example here
I've also stumbled upon this issue where the idea was to add a chain method .when() for describe and it, which will do pretty much the same I've described above. It may look nicer but is a bit harder to implement.
describe('foo', function () {
it('bar', function () {
// ...
}).when(anything);
}).when(something);
If you are really interested in this second approach, I'll be happy to play with it a little bit more and try to implement chain .when().
Update:
Jasmine uses third argument as a timeout option (see docs), so my code sample is replacing this feature, which is not ok. I like #milanlempera and #MarcoCI answers better, mine seems kinda hacky and not intuitive. I'll try to update my solution anyways soon not to break compatibilty with Jasmine default features.
I can share my experience with this.
In our environment we have several tests running with different browsers and different technologies.
In order to run always the same suites on all the platforms and browsers we have a helper file loaded in karma (helper.js) with some feature detection functions loaded globally.
I.e.
function isFullScreenSupported(){
// run some feature detection code here
}
You can use also Modernizr for this as well.
In our tests then we wrap things in if/else blocks like the following:
it('should work with fullscreen', function(){
if(isFullScreenSupported()){
// run the test
}
// don't do anything otherwise
});
or for an async test
it('should work with fullscreen', function(done){
if(isFullScreenSupported()){
// run the test
...
done();
} else {
done();
}
});
While it's a bit verbose it will save you time for the kind of scenario you're facing.
In some cases you can use user agent sniffing to detect a particular browser type or version - I know it is bad practice but sometimes there's effectively no other way.
Try this. I am using this solution in my projects.
it('should do something', function () {
if (!/PhantomJS/.test(window.navigator.userAgent)) {
expect(true).to.be.true;
}
});
This will not run this particular test in PhantomJS, but will run it in other browsers.
Just rename the tests that you want to disable from it(...) to xit(...)
function xit: A temporarily disabled it. The spec will report as
pending and will not be executed.
The issue is to test the event handlers with asynchronous internal methods, which is executed by SDK like facebook.
the plain test is:
describe('Listens to someevent', function () {
it('and triggers anotherevent', function () {
var eventSpy = spyOnEvent(document, 'anotherevent');
var data = {
param1: 'param1',
param2: 'param2',
}
this.component.trigger('somevent', data);
runs(function() {
expect(eventSpy).toHaveBeenTriggeredOn(document);
});
});
});
when someevent is triggered with options, the component handler is fired:
this.handler = function (e, data) {
SDK.apicall(data, function (err, response) {
if (!err) {
doSomething();
}
// trigger data event
that.trigger(document, 'anotherevent');
});
}
;
};
In jasmine 1.3 and before, a runs without a preceding waitsFor still executes immediately. It's really the waitsFor that makes the spec asynchronous. This has changed in 2.0.
Alternatively, if you don't really want to call the external API during your tests. You can use something like jasmine-ajax (docs). This will allow you to return the ajax call immediately in test with whatever response you want to test with. This has the advantage of making your specs faster (there's no waiting for the API), and make your specs less dependent on the API being up when they run.