chai-signals

Adds chai assertions for the js-signals library.

Adds the following assertions to chai:

• dispatched()
• dispatchedWith()

How to use

Installation

Important: The expectations in this package are dependent on signals from js-signals.

npm install chai-signals

Create

First define which signals you're interested in.

var signal = new signals.Signal();
var signalSpy = chai.signals.spyOnSignal(signal);
var signalSpies = chai.signals.createSignalSpyObj([signal1, signal2]);

Filtering signals

You can pass a boolean function to specify which dispatches to register.

var signal = new signals.Signal();
var signalSpy = chai.signals.spyOnSignal(signal).matching(function (dispatchInfo) {
    return dispatchInfo !== null;
});
signal.dispatch();  // ignored
signal.dispatch(5); // registered

Expectations

After defining the spy you can set expectations in your tests.

expect(signalSpy).to.have.been.dispatched();        // the spy's signal has been dispatched at least once
expect(signalSpy).to.have.been.dispatched(n);       // the spy's signal has been dispatched n times
expect(signal).to.have.been.dispatched();           // the signal has been dispatched at least once
expect(signal).to.have.been.dispatched(n);          // the signal has been dispatched n times
expect(signalSpy).to.not.have.been.dispatched();    // the spy's signal has not been dispatched at all
expect(signalSpy).to.not.have.been.dispatched(n);   // the spy's signal has not been dispatched n times
expect(signal).to.not.have.been.dispatched();       // the signal has not been dispatched at all
expect(signal).to.not.have.been.dispatched(n);      // the signal has not been dispatched at all
 
expect(signalSpy).to.have.been.dispatchedWith(n);          // the spy's signal has been dispatched using n
expect(signalSpy).to.have.been.dispatchedWith(m, n);       // the spy's signal has been dispatched using (m, n)
expect(signalSpy).to.have.been.dispatchedWith(<object>);   // the spy's signal has been dispatched with using object
expect(signal).to.have.been.dispatchedWith(n);          // the signal has been dispatched using n
expect(signal).to.have.been.dispatchedWith(m, n);       // the signal has been dispatched using (m, n)
expect(signal).to.have.been.dispatchedWith(<object>);   // the signal has been dispatched with using object
expect(signalSpy).to.not.have.been.dispatchedWith(n);          // the spy's signal has not been dispatched using n
expect(signalSpy).to.not.have.been.dispatchedWith(m, n);       // the spy's signal has not been dispatched using (m, n)
expect(signalSpy).to.not.have.been.dispatchedWith(<object>);   // the spy's signal has not been dispatched with using object
expect(signal).to.not.have.been.dispatchedWith(n);          // the signal has not been dispatched using n
expect(signal).to.not.have.been.dispatchedWith(m, n);       // the signal has not been dispatched using (m, n)
expect(signal).to.not.have.been.dispatchedWith(<object>);   // the signal has not been dispatched with using object

AMD

It's possible to use chai-signals as an AMD (Asynchronous Module Definition) module.

chai-signals depends on JS-Signals, so first define signals path:

require.config({
    paths: {
        signals: 'components/js-signals/signals',
        chai-signals: 'components/chai-signals/lib/chai-signals'
    }
});

Then use it in Chai tests like this:

define(['myClass', 'chaiSignals'], function(myClass, chaiSignals) {
    it('should signal completed', function () {
        chai.signals.spyOnSignal(myClass.completed);
 
        myClass.doSomething();
 
        expect(myClass.completed).to.have.been.dispatched();
    });
});

If you are using karma to run tests make sure to include chai.use(chaiSignals); in each of your test files.

Examples

See tests for usage:

chai-signals.test.js

Development

Install node.js, bower.

npm install
bower install
npm test

License

This code is distributed under the MIT license.

Credit

This plugin is based off of Adam Nowotny's jasmine-signals.