Sinon.JS Assertions for Chai

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Sinon–Chai provides a set of custom assertions for using the [Sinon.JS][] spy, stub, and mocking framework with the
[Chai][] assertion library. You get all the benefits of Chai with all the powerful tools of Sinon.JS.

Instead of using Sinon.JS's assertions:

``javascript
sinon.assertCalledWith(mySpy, "foo");
`

or awkwardly trying to use Chai's should or expect interfaces on spy properties:

`javascript
mySpy.calledWith("foo").should.be.ok;
expect(mySpy.calledWith("foo")).to.be.ok;
`

you can say

`javascript
mySpy.should.have.been.calledWith("foo");
expect(mySpy).to.have.been.calledWith("foo");
`

Assertions

All of your favorite Sinon.JS assertions made their way into Sinon–Chai. We show the should syntax here; the expect
equivalent is also available.

For more information on the behavior of each assertion, see
[the documentation for the corresponding spy methods][spymethods]. These of course work on not only spies, but
individual spy calls, stubs, and mocks as well.

Note that you can negate any assertion with Chai's .not. E. g. for notCalled use spy.should.have.not.been.called.

For assert interface there is no need for this library. You can install [Sinon.JS assertions][sinonassertions] right into Chai's assert object with expose:

`javascript
var chai = require("chai");
var sinon = require("sinon");

sinon.assert.expose(chai.assert, { prefix: "" });
`

Examples

Using Chai's should:

`javascript
"use strict";
var chai = require("chai");
var sinon = require("sinon");
var sinonChai = require("sinon-chai");
chai.should();
chai.use(sinonChai);

function hello(name, cb) {
cb("hello " + name);
}

describe("hello", function () {
it("should call callback with correct greeting", function () {
var cb = sinon.spy();

hello("foo", cb);

cb.should.have.been.calledWith("hello foo");
});
});
`

Using Chai's expect:

`javascript
"use strict";
var chai = require("chai");
var sinon = require("sinon");
var sinonChai = require("sinon-chai");
var expect = chai.expect;
chai.use(sinonChai);

function hello(name, cb) {
cb("hello " + name);
}

describe("hello", function () {
it("should call callback with correct greeting", function () {
var cb = sinon.spy();

hello("foo", cb);

expect(cb).to.have.been.calledWith("hello foo");
});
});
`

Installation and Usage

$3

Do an npm install sinon-chai to get up and running. Then:

`javascript
var chai = require("chai");
var sinonChai = require("sinon-chai");

chai.use(sinonChai);
`

You can of course put this code in a common test fixture file; for an example using [Mocha][], see
[the Sinon–Chai tests themselves][fixturedemo].

$3

Sinon–Chai supports being used as an [AMD][] module, registering itself anonymously (just like Chai). So, assuming you
have configured your loader to map the Chai and Sinon–Chai files to the respective module IDs "chai" and
"sinon-chai", you can use them as follows:

`javascript
define(function (require, exports, module) {
var chai = require("chai");
var sinonChai = require("sinon-chai");

chai.use(sinonChai);
});
`

$3

If you include Sinon–Chai directly with a


``

$3

Thanks to [Cymen Vig][], there's now [a Ruby gem][] of Sinon–Chai that integrates it with the Rails asset pipeline!

[Sinon.JS]: http://sinonjs.org/
[Chai]: http://chaijs.com/
[spymethods]: http://sinonjs.org/docs/#spies-api
[sinonassertions]: http://sinonjs.org/docs/#assertions
[Mocha]: https://mochajs.org/
[fixturedemo]: https://github.com/domenic/sinon-chai/tree/master/test/
[AMD]: https://github.com/amdjs/amdjs-api/wiki/AMD
[Cymen Vig]: https://github.com/cymen
[a Ruby gem]: https://github.com/cymen/sinon-chai-rails

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