Introduction

Ristretto is a browser friendly assertion library for Mocha.

The library exists mainly because Chai's assert API doesn't work in older versions of Internet Explorer. If you want to use an assert-style assertion API with Mocha and you want to run your tests in IE 8 or older then Ristretto is for you.

Using Ristretto

Ristretto is intended to be used as an AMD module in conjuction with an AMD loader like RequireJS or curl, e.g.

require(['ristretto', 'something'], function (assert, something) {
	describe('something', function () {
		describe('method', function () {
    		it('should work', function () {
    			var actual = something.method();

    			assert.isTrue(actual);
    		});
		});
	});
});

Whilst using modules is highly recommended, it is possible to use Ristretto without using AMD modules. If AMD support is not detected ristretto is attached to the window object, e.g.

(function () {
    var assert = window.ristretto;

	describe('something', function () {
		describe('method', function () {
    		it('should work', function () {
    			var actual = something.method();

    			assert.isTrue(actual);
    		});
		});
	});
} ());

Package Manager Support

Ristretto is available as a JamJS package. To install Ristretto via Jam first install Jam:

npm install -g jamjs

Then install Ristretto in your project directory:

jam install ristretto

Ristretto is also available as a Bower package. To install Ristretto via Bower first install Bower:

npm install -g bower

Then install Ristretto in your project directory:

bower install ristretto

API

Testing Truthiness

require(['ristretto'], function (assert) {
	describe('something', function () {
		it('should be truthy', function () {
			var actual = 1;

			assert.isTruthy(actual);
			// you could also express this as
			assert.truthy(actual);
			// or
			assert(actual);
		});

		it('should be falsey', function () {
			var actual = 0;

			assert.isFalsey(actual);
			// you could also express this as
			assert.falsey(actual);
			// or
			assert(!actual);
		});
	});
});

Equality

require(['ristretto', 'something'], function (assert, something) {
	describe('something', function () {
		describe('method', function () {
    		it('should equal 1', function () {
    			var expected = 1,
    				actual = something.method();

    			assert.strictEqual(actual, expected);
    			// you could also express this as
    			assert(actual === expected);
    			// or, although things can be equal that aren't strictEqual
    			assert.equal(actual, expected);
    		});

    		it('should not equal 2', function () {
    			var expected = 2,
    				actual = something.method();

    			assert.strictNotEqual(actual, expected);
    			// you could also express this as
    			assert(actual !== expected);
    			// or, although things can be strictNotEqual that aren't notEqual
    			assert.notEqual(actual, expected);
    		});
		});
	});
});

Deep Equality

requre(['ristretto'], function (assert) {
	describe('something', function () {
		var actual = [1, 2, 3],
			expected = [1, 2, 3];

		assert.deepEqual(actual, expected);
	});
});

Failure

require(['ristretto', 'testable'], function (assert, Testable) {
	describe('testable', function () {
		describe('method', function () {
    		it('should not fire an "invoked" event', function () {
				var testable = new Testable();

				testable.on('invoked', function () {
					assert.fail('"invoked" event should not be fired');
				});

				testable.method();
			});
		});
	});
});