Beautiful assertion library.

npm install alright
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Build Status NPM version Dependencies Status experimental

browser support

Beautiful assertion library.


  • Straight-forward: Alright should get out of your way and just let you define your tests with what you already know: plain JavaScript.

  • No verbosity: We don't want expect(x)

  • Helpful error messages: When things go wrong, Alright should do its best to show you exactly what's wrong and how you might fix it.

  • Test-framework agnostic: Alright should work with anything that expect Errors to be thrown when assertions fail.

  • Extensible: It should be easy to extend the built-in assertions with plain JavaScript.

  • Work with older Browsers: Some people still need to support old IEs, Alright should work on them.


Using the Sweet.js macros:

// for macros to work, you need to use 'alright' as your identifier
var alright = require('alright')

// simple assertions
add(a)(b) => a + b
add(a)(b) => not a + b

// anything goes assertions
add(a)(b) should equal(a + b)
add(a)(b) should not equal(a + b)

// asynchronous assertions with pure fantasy-land monads
asyncAdd(a)(b) will => a + b
asyncAdd(a)(b) will not => a + b
asyncAdd(a)(b) will be equal(a + b)
asyncAdd(a)(b) will not be equal(a + b)

Using vanilla JavaScript:

var _ = require('alright')

_.verify(_.equals(a + b, add(a)(b)))
_.verify(_.not(_.equals(a + b, add(a)(b))))

asyncAdd(a)(b).chain(function(x) {
  return _.verify(_.equals(a + b, x))


The easiest way is to grab it from NPM. If you're running in a Browser environment, you can use [Browserify][]

$ npm install alright

Using with CommonJS

If you're not using NPM, [Download the latest release][release], and require the alright.umd.js file:

var Alright = require('alright')

Using with AMD

[Download the latest release][release], and require the alright.umd.js file:

require(['alright'], function(Alright) {
  ( ... )

Using without modules

[Download the latest release][release], and load the alright.umd.js file. The properties are exposed in the global Alright object:

<script src="/path/to/alright.umd.js"></script>

Compiling from source

If you want to compile this library from the source, you'll need [Git][], [Make][], [Node.js][], and run the following commands:

$ git clone git://
$ cd alright
$ npm install
$ make bundle

This will generate the dist/alright.umd.js file, which you can load in any JavaScript environment.


You can [read the documentation online][docs] or build it yourself:

$ git clone git://
$ cd alright
$ npm install
$ make documentation

Then open the file docs/index.html in your browser.

Platform support

This library assumes an ES5 environment, but can be easily supported in ES3 platforms by the use of shims. Just include [es5-shim][] :)


Copyright (c) 2014 Quildreen Motta.

Released under the MIT licence.

[Fantasy Land]: [Browserify]: [Git]: [Make]: [Node.js]: [es5-shim]: [docs]: [release]:
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