README
Counterfeit
Counterfeit is an AngularJS module, that provides test doubles for asynchronous promises.
This library facilitates the stubbing of functions that return promises. Providing users with easy access to resolve/reject fake promises.
Installation
Install the module via npm
$ npm install counterfeit --save-dev
If you are using the Karma test runner then you will need to add counterfeit to the files list in your Karma configuration:
module.exports = function(config) {
config.set({
files: [
'node_modules/counterfeit/dist/counterfeit.js'
],
...
});
}
Example Usage
To demonstrate how counterfeit
can be used to facilitate testing,
consider the following AngularJS module called starWars
:
var starWars = angular.module("starWars", ["ngResource"]);
starWars.service('DeflectorShield', function($resource) {
return $resource({}, null, {
"reboot": {
method: "PUT",
url: "/starwars/deflector_shield/reboot"
}
});
});
starWars.factory('DeathStar', function(DeflectorShield) {
var status, shieldStatus;
shieldStatus = function(msg) {
status = msg;
};
return {
rebootDeflectorShield: function() {
DeflectorShield.reboot().$promise.then(
shieldStatus, shieldStatus, shieldStatus);
},
shieldStatus: function() {
return status;
},
}
});
As can be seen the DeathStar
factory uses the DeflectorShield
service, that exposes one public method called reboot
. This method
returns a promise. This presents a challenge for the testing of the
DeathStar
factory because the rebootDeflectorShield
method relies
upon an asynchronous operation that returns a promise.
In order to test the functionality of DeathStar.rebootDeflectorShield
we need a way of controlling when the promise returned from
DeflectorShield.reboot
is resolved/rejected. This is where
counterfeit
comes into play.
The following DeathStar
test (using mocha,
chai and sinon) is setup to
decorate the DeflectorShield
service so that the reboot
method is a
CounterfeitStub
. This stub is configured to return a
CounterfeitPromise
, which can be conveniently resolved within the
test, allowing assertions to be made against DeathStar
behaviour that
is asynchronous.
describe('DeathStar', function() {
var promise, deathStar;
beforeEach(function() {
module("counterfeit");
module("starWars");
module(function($provide) {
$provide.decorator("DeflectorShield", function($delegate, counterfeit) {
promise = counterfeit.promise();
$delegate.reboot = counterfeit.stub(promise);
return $delegate;
});
});
inject(function(DeathStar) {
deathStar = DeathStar;
});
});
describe("#rebootDeflectorShield", function() {
describe("when reboot in progress", function() {
it("sets shield status", function() {
deathStar.rebootDeflectorShield();
promise.notify("Shield rebooting");
expect(deathStar.shieldStatus()).to.eql("Shield rebooting");
});
});
describe("when successfully rebooted", function() {
it("sets shield status", function() {
deathStar.rebootDeflectorShield();
promise.resolve("All systems are operational");
expect(deathStar.shieldStatus()).to.eql("All systems are operational");
});
});
describe("when reboot fails", function() {
it("sets shield status", function() {
deathStar.rebootDeflectorShield();
promise.reject("Shield malfunction");
expect(deathStar.shieldStatus()).to.eql("Shield malfunction");
});
});
});
});
Contributing
- Fork it
- Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am 'Add some feature'
) - Push to the branch (
git push origin my-new-feature
) - Create new Pull Request
License
This project rocks and uses MIT-LICENSE.