unexpected

Unexpected

Minimalistic BDD assertion toolkit based on expect.js

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

Run the test in the browser

Features

• Fast
• Provides really nice error messages
• Helps you if you misspells assertions
• Compatible with all test frameworks.
• Node.JS ready (require('unexpected')).
• Single global with no prototype extensions or shims.
• Cross-browser: works on IE6+, Firefox, Safari, Chrome, Opera.

How to use

Node

Install it with NPM or add it to your package.json:

$ npm install unexpected

Then:

var expect = require('unexpected');

Browser

Include the unexpected.js found at the lib directory of this repository.

<script src="unexpected.js"></script>

this will expose the expect function under the following namespace:

var expect = weknowhow.expect;

RequireJS

Include the library with RequireJS the following way:

define(['unexpected/lib/unexpected'], function (expect) {
   // Your code
});

API

to be ok

asserts that the value is truthy

ok / truthy / falsy: asserts that the value is truthy or not

expect(1, 'to be ok');
expect(true, 'to be ok');
expect(true, 'not to be falsy');
expect({}, 'to be truthy');
expect(0, 'not to be ok');
expect(0, 'to be falsy');
expect(null, 'to be falsy');
expect(undefined, 'to be falsy');

be: asserts === equality

expect(obj, 'to be', obj);
expect(obj, 'not to be', {});
expect(1, 'to be', 1);
expect(1, 'not to be', true);
expect('1', 'not to be', 1);
expect(null, 'not to be', undefined);
expect(null, 'to be null');
expect(0, 'not to be null');
expect(undefined, 'not to be null');
expect(true, 'to be true');
expect(false, 'not to be true');
expect(false, 'to be false');
expect(true, 'not to be false');
expect(undefined, 'to be undefined');

equal: asserts loose equality that works with objects

expect({ a: 'b' }, 'to equal', { a: 'b' });
expect(1, 'to equal', '1');
expect(null, 'not to equal', '1');
var now = new Date();
expect(now, 'to equal', now);
expect(now, 'to equal', new Date(now.getTime()));
expect({ now: now }, 'to equal', { now: now });

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

expect(5, 'to be a', 'number');
expect(5, 'to be a number');

expect('abc', 'to be a', 'string');
expect('abc', 'to be a string');
expect('', 'to be an empty string');
expect('abc', 'to be a non-empty string');

expect([], 'to be an', 'array');
expect([], 'to be an array');
expect([], 'to be an', Array);
expect([], 'to be an empty array');
expect([123], 'to be a non-empty array');

expect({foo: 123}, 'to be an', 'object');
expect({foo: 123}, 'to be an object');
expect({foo: 123}, 'to be a non-empty object');
expect({}, 'to be an empty object');

expect(null, 'not to be an', 'object');
expect(null, 'not to be an object');

expect(true, 'to be a', 'boolean');
expect(true, 'to be a boolean');

expect(expect, 'to be a', 'function');
expect(expect, 'to be a function');

NaN: asserts that the value is NaN

expect(NaN, 'to be NaN');
expect({}, 'to be NaN');
expect(2, 'not to be NaN');
expect(null, 'not to be NaN');
expect(undefined, 'to be NaN');
expect("String", 'to be NaN');

match: asserts String regular expression match

expect('test', 'to match', /.*st/);
expect('test', 'not to match', /foo/);
expect(null, 'not to match', /foo/);

contain: asserts indexOf for an array or string

expect([1, 2], 'to contain', 1);
expect('hello world', 'to contain', 'world');
expect(null, 'not to contain', 'world');

length: asserts array .length

expect([], 'to have length', 0);
expect([1,2,3], 'to have length', 3);
expect([1,2,3], 'not to have length', 4);

empty: asserts that an array is empty or not

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

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

expect([1, 2], 'to have property', 'length');
expect([1, 2], 'to have property', 'length', 2);
expect({a: 'b'}, 'to have property', 'a');
expect({a: 'b'}, 'to have property', 'a', 'b');
expect({a: 'b'}, 'to have property', 'toString');
expect({a: 'b'}, 'to have own property', 'a');
expect(Object.create({a: 'b'}), 'not to have own property', 'a');

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

expect(null, 'not to have key', 'a');
expect({ a: 'b' }, 'to have key', 'a');
expect({ a: 'b' }, 'not to have key', 'b');
expect({ a: 'b', c: 'd' }, 'to not only have key', 'a');
expect({ a: 'b', c: 'd' }, 'to only have keys', 'a', 'c');
expect({ a: 'b', c: 'd' }, 'to only have keys', ['a', 'c']);
expect({ a: 'b', c: 'd', e: 'f' }, 'to not only have keys', ['a', 'c']);

throw exception / throw error / throw: asserts that the Function throws or not when called

expect(fn, 'to throw exception');
expect(fn, 'to throw');
expect(fn, 'to throw exception', function (e) { // get the exception object
  expect(e, 'to be a', SyntaxError);
});
expect(fn, 'to throw exception', /matches the exception message/);
expect(fn, 'to throw error', 'matches the exact exception message');
expect(fn2, 'not to throw error');

finite/infinite: asserts a finite or infinite number

expect(123, 'to be finite');
expect(Infinity, 'not to be finite');
expect(Infinity, 'to be infinite');
expect(false, 'not to be infinite');

within: asserts a number within a range

expect(0, 'to be within', 0, 4);
expect(1, 'to be within', 0, 4);
expect(4, 'to be within', 0, 4);
expect(-1, 'not to be within', 0, 4);
expect(5, 'not to be within', 0, 4);

greater than / above: asserts >

expect(3, 'to be greater than', 2);
expect(1, 'to be above', 0);
expect(4, 'to be >', 3);
expect(4, '>', 3);

greater than or equal to: asserts >

expect(3, 'to be greater than or equal to', 2);
expect(3, 'to be >=', 3);
expect(3, '>=', 3);

less than / below: asserts <

expect(0, 'to be less than', 4);
expect(0, 'to be below', 1);
expect(3, 'to be <', 4);
expect(3, '<', 4);

less than or equal to: asserts >

expect(0, 'to be less than or equal to', 4);
expect(4, 'to be <=', 4);
expect(3, '<=', 4);

positive: assert that a number is positive

expect(3, 'to be positive');

negative: assert that a number is negative

expect(-1, 'to be negative');

fail: explicitly forces failure.

expect.fail()
expect.fail('Custom failure message')
expect.fail('{0} was expected to be {1}', 0, 'zero');

array whose items satify: will run an assertion function for each items in an array

expect([0, 1, 2, 3, 4], 'to be an array whose items satisfy', function (item) {
    expect(item, 'to be a number');
});

expect([0, 1, 2, 3, 4], 'to be an array whose items satisfy', 'to be a number');

expect([[1], [2]], 'to be an array whose items satisfy',
       'to be an array whose items satisfy', 'to be a number');

expect([[], []], 'to be a non-empty array whose items satisfy', function (item) {
    expect(item, 'to be an empty array');
});

Using this assertion result in very detailed error reporting show in the below example:

expect([[0, 1, 2], [4, '5', 6], [7, 8, '9']],
       'to be an array whose items satisfy', function (arr) {
    expect(arr, 'to be an array whose items satisfy', function (item) {
        expect(item, 'to be a number');
    });
});

will output:

failed expectation in [ [ 0, 1, 2 ], [ 4, '5', 6 ], [ 7, 8, '9' ] ]:
    1: failed expectation in [ 4, '5', 6 ]:
        1: expected '5' to be a 'number'
    2: failed expectation in [ 7, 8, '9' ]:
        2: expected '9' to be a 'number'

map whose keys satify: will run an assertion function for each key in a map

expect({ foo: 0, bar: 1, baz: 2, qux: 3 },
       'to be a map whose keys satisfy', function (key) {
    expect(key, 'to match', /^[a-z]{3}$/);
});

expect({ foo: 0, bar: 1, baz: 2, qux: 3 },
       'to be a map whose keys satisfy',
       'to match', /^[a-z]{3}$/);

Using this assertion result in very detailed error reporting show in the below example:

expect({ foo: 0, bar: 1, baz: 2, qux: 3, quux: 4 },
       'to be a map whose keys satisfy', function (key) {
    expect(key, 'to have length', 3);
});

will output:

failed expectation on keys foo, bar, baz, qux, quux:
    quux: expected 'quux' to have length 3

map whose values satify: will run an assertion function for each value in a map

expect({ foo: 0, bar: 1, baz: 2, qux: 3 },
       'to be a map whose values satisfy', function (value) {
    expect(value, 'to be a number');
});

expect({ foo: 0, bar: 1, baz: 2, qux: 3 },
       'to be a map whose values satisfy',
       'to be a number');

Using this assertion result in very detailed error reporting show in the below example:

expect({ foo: [0, 1, 2], bar: [4, '5', 6], baz: [7, 8, '9'] },
       'to be a map whose values satisfy', function (arr) {
    expect(arr, 'to be an array whose items satisfy', function (item) {
        expect(item, 'to be a number');
    });
});

will output:

failed expectation in
{ foo: [ 0, 1, 2 ],
  bar: [ 4, '5', 6 ],
  baz: [ 7, 8, '9' ] }:
    bar: failed expectation in [ 4, '5', 6 ]:
        1: expected '5' to be a 'number'
    baz: failed expectation in [ 7, 8, '9' ]:
        2: expected '9' to be a 'number'

Print all registered assertions to the console

console.log(expect.toString());

Using Unexpected 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 () {
    expect(add, 'to be a', 'function');
  });

  it('should do math', function () {
    expect(add(1, 3), 'to be', 4);
  });
});

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

Running tests

Clone the repository and install the developer dependencies:

git clone git://github.com/sunesimonsen/unexpected.git unexpected
cd unexpected && npm install

Node

npm test

Credits

(The MIT License)

Copyright (c) 2013 Sune Simonsen <[e-mail]>

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 expect.js by Guillermo Rauch - MIT.

Changelog

v1.0.12

• Set the showDiff property of the thrown errors under the same circumstances as expected/actual, provided that the types are non-primitive and the same. (Andreas Lind Petersen)
• Updated readme to avoid scrolling in examples (Sune Simonsen)