xpect - A LearnBoost/expect.js fork

Minimalistic BDD assertion toolkit based on should.js

xpect(window.r).to.be(undefined);
xpect({ a: 'b' }).to.eql({ a: 'b' })
xpect(5).to.be.a('number');
xpect([]).to.be.an('array');
xpect(window).not.to.be.an(Image);

Features

expect

• Cross-browser: works on IE6+, Firefox, Safari, Chrome, Opera.
• Compatible with all test frameworks.
• Node.JS ready (npm install xpect).
• Standalone. Single global with no prototype extensions or shims.

additional features beyond expect

• AMD support (not easy to achieve with expect.js because of the .js prefix in its package name)
• AMD, CommonJS and Browser-Globals support by UMD
• bower.io support (bower install xpect)
• component support (component install xpect)
• and, most importantly, same AMD and CommonJS package name

How to use

CommonJS (Node.js)

var xpect = require('xpect');
xpect(42).to.be.ok();

Browser Globals

<script src="xpect.js"></script>
<script>
  xpect(42).to.be.ok();
</script>

AMD

define(['xpect'] , function (xpect) {
  xpect(42).to.be.ok();
});

API

ok: asserts that the value is truthy or not

xpect(1).to.be.ok();
xpect(true).to.be.ok();
xpect({}).to.be.ok();
xpect(0).to.not.be.ok();

be / equal: asserts === equality

xpect(1).to.be(1)
xpect(NaN).not.to.equal(NaN);
xpect(1).not.to.be(true)
xpect('1').to.not.be(1);

eql: asserts loose equality that works with objects

xpect({ a: 'b' }).to.eql({ a: 'b' });
xpect(1).to.eql('1');

a/an: asserts typeof with support for array type and instanceof

// typeof with optional `array`
xpect(5).to.be.a('number');
xpect([]).to.be.an('array');  // works
xpect([]).to.be.an('object'); // works too, since it uses `typeof`

// constructors
xpect(5).to.be.a(Number);
xpect([]).to.be.an(Array);
xpect(tobi).to.be.a(Ferret);
xpect(person).to.be.a(Mammal);

match: asserts String regular expression match

xpect(program.version).to.match(/[0-9]+\.[0-9]+\.[0-9]+/);

contain: asserts indexOf for an array or string

xpect([1, 2]).to.contain(1);
xpect('hello world').to.contain('world');

length: asserts array .length

xpect([]).to.have.length(0);
xpect([1,2,3]).to.have.length(3);

empty: asserts that an array is empty or not

xpect([]).to.be.empty();
xpect({}).to.be.empty();
xpect({ length: 0, duck: 'typing' }).to.be.empty();
xpect({ my: 'object' }).to.not.be.empty();
xpect([1,2,3]).to.not.be.empty();

property: asserts presence of an own property (and value optionally)

xpect(window).to.have.property('xpect')
xpect(window).to.have.property('xpect', xpect)
xpect({a: 'b'}).to.have.property('a');

key/keys: asserts the presence of a key. Supports the only modifier

xpect({ a: 'b' }).to.have.key('a');
xpect({ a: 'b', c: 'd' }).to.only.have.keys('a', 'c');
xpect({ a: 'b', c: 'd' }).to.only.have.keys(['a', 'c']);
xpect({ a: 'b', c: 'd' }).to.not.only.have.key('a');

throwException/throwError: asserts that the Function throws or not when called

xpect(fn).to.throwError(); // synonym of throwException
xpect(fn).to.throwException(function (e) { // get the exception object
  xpect(e).to.be.a(SyntaxError);
});
xpect(fn).to.throwException(/matches the exception message/);
xpect(fn2).to.not.throwException();

withArgs: creates anonymous function to call fn with arguments

xpect(fn).withArgs(invalid, arg).to.throwException();
xpect(fn).withArgs(valid, arg).to.not.throwException();

within: asserts a number within a range

xpect(1).to.be.within(0, Infinity);

greaterThan/above: asserts >

xpect(3).to.be.above(0);
xpect(5).to.be.greaterThan(3);

lessThan/below: asserts <

xpect(0).to.be.below(3);
xpect(1).to.be.lessThan(3);

fail: explicitly forces failure.

xpect().fail()
xpect().fail("Custom failure message")

Using with a test framework

For example, if you create a test suite with mocha.

Let's say we wanted to test the following program:

math.js

function add (a, b) { return a + b; };

Our test file would look like this:

describe('test suite', function () {
  it('should expose a function', function () {
    xpect(add).to.be.a('function');
  });

  it('should do math', function () {
    xpect(add(1, 3)).to.equal(4);
  });
});

If a certain xpectation fails, an exception will be raised which gets captured and shown/processed by the test runner.

Differences with should.js

• No need for static should methods like should.strictEqual. For example, xpect(obj).to.be(undefined) works well.
• Some API simplifications / changes.
• API changes related to browser compatibility.

Running tests

# install xpect and devDependencies
npm install xpect
cd node_modules/xpect
npm install
npm run install-browser-test

# node
npm test

# browser
npm run browser-test
xdg-open http://localhost:3000/test/

Credits

(The MIT License)

Copyright (c) 2011 Guillermo Rauch <[email protected]>

Portions (c) 2014 Michael Mayer <[email protected]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

3rd-party

Heavily borrows from should.js by TJ Holowaychuck - MIT.