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:
sinon.assertCalledWith(mySpy, "foo");
or awkwardly trying to use Chai's should
or expect
interfaces on spy properties:
mySpy.calledWith("foo").should.be.ok;
expect(mySpy.calledWith("foo")).to.be.ok;
you can say
mySpy.should.have.been.calledWith("foo");
expect(mySpy).to.have.been.calledWith("foo");
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.
Sinon.JS property/method | Sinon–Chai assertion |
---|---|
called | spy.should.have.been.called |
callCount | spy.should.have.callCount(n) |
calledOnce | spy.should.have.been.calledOnce |
calledTwice | spy.should.have.been.calledTwice |
calledThrice | spy.should.have.been.calledThrice |
calledBefore | spy1.should.have.been.calledBefore(spy2) |
calledAfter | spy1.should.have.been.calledAfter(spy2) |
calledWithNew | spy.should.have.been.calledWithNew |
alwaysCalledWithNew | spy.should.always.have.been.calledWithNew |
calledOn | spy.should.have.been.calledOn(context) |
alwaysCalledOn | spy.should.always.have.been.calledOn(context) |
calledWith | spy.should.have.been.calledWith(...args) |
alwaysCalledWith | spy.should.always.have.been.calledWith(...args) |
calledWithExactly | spy.should.have.been.calledWithExactly(...args) |
alwaysCalledWithExactly | spy.should.always.have.been.calledWithExactly(...args) |
calledWithMatch | spy.should.have.been.calledWithMatch(...args) |
alwaysCalledWithMatch | spy.should.always.have.been.calledWithMatch(...args) |
returned | spy.should.have.returned(returnVal) |
alwaysReturned | spy.should.have.always.returned(returnVal) |
threw | spy.should.have.thrown(errorObjOrErrorTypeStringOrNothing) |
alwaysThrew | spy.should.have.always.thrown(errorObjOrErrorTypeStringOrNothing) |
For more information on the behavior of each assertion, see the documentation for the corresponding spy methods. These of course work on not only spies, but individual spy calls, stubs, and mocks as well.
Using Chai's should
:
"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
:
"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");
});
});
Do an npm install sinon-chai
to get up and running. Then:
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.
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:
define(function (require, exports, module) {
var chai = require("chai");
var sinonChai = require("sinon-chai");
chai.use(sinonChai);
});
If you include Sinon–Chai directly with a <script>
tag, after the one for Chai itself, then it will automatically plug
in to Chai and be ready for use. Note that you'll want to get the latest browser build of Sinon.JS as well:
<script src="chai.js"></script>
<script src="sinon-chai.js"></script>
<script src="sinon.js"></script>
Thanks to Cymen Vig, there's now a Ruby gem of Sinon–Chai that integrates it with the Rails asset pipeline!