sinon-as-promised

sinon-as-promised

Sugar methods for using sinon.js stubs with promises.

Getting Started

var sinon           = require('sinon');
var sinonAsPromised = require('sinon-as-promised');

You'll only need to require sinon-as-promised once. It attaches the appropriate stubbing functions which will then be available anywhere else you require sinon. You'll probably want to call it in a setup file that is required before your tests. It defaults to Bluebird, but you can use another promise library if you'd like, as long as it exposes a constructor:

// Using RSVP
var RSVP            = require('rsvp');
var sinonAsPromised = require('sinon-as-promised')(RSVP.Promise);
// ES6 promises
var sinonAsPromised = require('sinon-as-promised')(Promise);

Usage

stub.resolves(value)

When called, the stub will return a promise which resolves with the provided value.

var stub = sinon.stub();
stub.resolves('foo');

stub().then(function (value) {
    // value === 'foo'
});

stub.onCall(0).resolves('bar')
stub().then(function (value) {
    // value === 'bar'
});

stub.rejects(error)

When called, the stub will return a promise which rejects with the provided error. If error is a string, it will be set as the error message.

stub.rejects(new Error('foo'))().catch(function (error) {
    // error.message === 'foo'
});
stub.rejects('foo')().catch(function (error) {
    // error.message === 'foo'
});

stub.onCall(0).rejects('bar');
stub().catch(function (error) {
    // error.message === 'bar'
});

Custom Scheduler

By default, sinon-as-promised schedules the resolution or rejection of your stub promises using process.nextTick in Node and setImmediate in the browser. This helps ensure that Bluebird's error handling mechanism does not treat rejections as "possibly unhandled" since you'll have a chance to attach an error handler while the promise is still pending.

Sometimes you may want to change this behavior, most commonly when using sinon-as-promised with Angular and $q. Angular allows you to flush the queue of deferred functions with $timeout.flush(). sinon-as-promised exposes a setScheduler method to allow you to override the default scheduling mechanism.

sinonAsPromised.setScheduler(fn) -> undefined

To replicate the default behavior:

sinonAsPromised.setScheduler(function (fn) {
  process.nextTick(fn);
});

To use with Angular:

sinonAsPromised($q);
sinonAsPromised.setScheduler(function (fn) {
  $rootScope.$evalAsync(fn);
});

Examples

• angular
• ES6
• Node or Browserify

License

MIT