tra-analysis/website/functions/node_modules/power-assert/README.md
2019-01-06 13:14:45 -06:00

987 lines
38 KiB
Markdown

[![power-assert][power-assert-banner]][power-assert-url]
Power Assert in JavaScript. Provides descriptive assertion messages through standard [assert](https://nodejs.org/api/assert.html) interface. No API is the best API.
[![Build Status][travis-image]][travis-url]
[![NPM package][npm-image]][npm-url]
[![Bower package][bower-image]][bower-url]
[![Dependency Status][depstat-image]][depstat-url]
[![License][license-image]][license-url]
DESCRIPTION
---------------------------------------
What is `power-assert`?
* is an implementation of "Power Assert" concept in JavaScript.
* provides descriptive assertion messages through standard [assert](https://nodejs.org/api/assert.html) interface.
* __No API is the best API__. With power-assert, __you don't need to learn many assertion library APIs__ (in most cases, all you need to remember is just an `assert(any_expression)` function)
* __Stop memorizing tons of assertion APIs. Just create expressions that return a truthy value or not__ and power-assert will show it to you right on the screen as part of your failure message without you having to type in a message at all.
* the core value of power-assert is absolute simplicity and stability. Especially, power-assert sticks to the simplest form of testing, `assert(any_expression)`.
* see slides: ["power-assert, mechanism and philosophy"](https://www.slideshare.net/t_wada/power-assert-nodefest-2014) -- talk at NodeFest 2014.
* __[NEW] Now you don't need `require('power-assert')` any more. Keep using `require('assert')`, and power-assert enhances them transparently.__ See slides: [From Library to Tool - power-assert as a General Purpose Assertion Enhancement Tool](https://speakerdeck.com/twada/from-library-to-tool-power-assert-as-a-general-purpose-assertion-enhancement-tool)
* to gain power-assert output, __you need to transform your test code__ to produce power-assert output.
* `power-assert - power = assert`. Without code transpilation, power-assert works just as normal `assert` does.
* fully compatible with [assert](https://nodejs.org/api/assert.html). So you can stop using power-assert and back to assert easily.
* has [online demo site](https://azu.github.io/power-assert-demo/).
* works both on server side and browser side.
* available via [npm](https://www.npmjs.com/package/power-assert) and [bower](https://bower.io/search/?q=power-assert).
* supports sourcemaps so you can debug as usual.
* provides [babel plugin](https://github.com/power-assert-js/babel-plugin-espower) and [babel preset](https://github.com/power-assert-js/babel-preset-power-assert).
* provides [browserify transform](https://github.com/power-assert-js/espowerify).
* provides [webpack loader](https://github.com/power-assert-js/webpack-espower-loader).
* provides [grunt task](https://github.com/power-assert-js/grunt-espower) and [gulp plugin](https://github.com/power-assert-js/gulp-espower).
* provides [command](https://github.com/power-assert-js/espower-cli).
* provides [custom module loader](https://github.com/power-assert-js/espower-loader) and its [convenient config module](https://github.com/power-assert-js/intelli-espower-loader).
* provides [Karma Adapter](https://github.com/power-assert-js/karma-power-assert) and [Karma Preprocessor](https://github.com/power-assert-js/karma-espower-preprocessor).
* supports ES6+ through [babel plugin](https://github.com/power-assert-js/babel-plugin-espower).
* supports [CoffeeScript](https://github.com/power-assert-js/espower-coffee).
* supports [TypeScript](https://github.com/power-assert-js/espower-typescript).
* has [TypeScript type definition](https://www.npmjs.com/package/@types/power-assert)
* has code migration tool that transforms existing code from [chai](https://github.com/twada/chai-to-assert), [should.js](https://github.com/node-modules/should2assert) and [expect.js](https://github.com/twada/expect-js-to-assert) to assert.
* [AVA](https://github.com/avajs/ava), the futuristic test runner, now [comes with power-assert builtin](https://github.com/avajs/ava#enhanced-assertion-messages)
* has [Lab transformer](https://github.com/feugy/lab-espower-transformer) to enable power-assert on [Lab](https://github.com/hapijs/lab)
* has [module loader](https://github.com/tracecomms/espower-ts-node) to get [ts-node](https://github.com/TypeStrong/ts-node) working together with power-assert
* [Wallaby.js](https://wallabyjs.com/) supports power-assert via [Babel compiler/preprocessor](https://github.com/wallabyjs/public/issues/754#issuecomment-241624868)
* pull-requests, issue reports and patches are always welcomed.
`power-assert` provides descriptive assertion messages for your tests, like this.
1) Array #indexOf() should return index when the value is present:
AssertionError: # path/to/test/mocha_node.js:10
assert(ary.indexOf(zero) === two)
| | | | |
| | | | 2
| -1 0 false
[1,2,3]
[number] two
=> 2
[number] ary.indexOf(zero)
=> -1
API
---------------------------------------
power-assert enhances these assert functions by [espower](https://github.com/power-assert-js/espower). Produces descriptive message when assertion is failed.
* [`assert(value, [message])`](https://nodejs.org/api/assert.html#assert_assert_value_message)
* [`assert.ok(value, [message])`](https://nodejs.org/api/assert.html#assert_assert_ok_value_message)
* [`assert.equal(actual, expected, [message])`](https://nodejs.org/api/assert.html#assert_assert_equal_actual_expected_message)
* [`assert.notEqual(actual, expected, [message])`](https://nodejs.org/api/assert.html#assert_assert_notequal_actual_expected_message)
* [`assert.strictEqual(actual, expected, [message])`](https://nodejs.org/api/assert.html#assert_assert_strictequal_actual_expected_message)
* [`assert.notStrictEqual(actual, expected, [message])`](https://nodejs.org/api/assert.html#assert_assert_notstrictequal_actual_expected_message)
* [`assert.deepEqual(actual, expected, [message])`](https://nodejs.org/api/assert.html#assert_assert_deepequal_actual_expected_message)
* [`assert.notDeepEqual(actual, expected, [message])`](https://nodejs.org/api/assert.html#assert_assert_notdeepequal_actual_expected_message)
* [`assert.deepStrictEqual(actual, expected, [message])`](https://nodejs.org/api/assert.html#assert_assert_deepstrictequal_actual_expected_message)
* [`assert.notDeepStrictEqual(actual, expected, [message])`](https://nodejs.org/api/assert.html#assert_assert_notdeepstrictequal_actual_expected_message)
power-assert is fully compatible with [assert](https://nodejs.org/api/assert.html). So functions below are also available though they are not enhanced (does not produce descriptive message).
* [`assert.fail(actual, expected, message, operator)`](https://nodejs.org/api/assert.html#assert_assert_fail_actual_expected_message_operator_stackstartfunction)
* [`assert.throws(block, [error], [message])`](https://nodejs.org/api/assert.html#assert_assert_throws_block_error_message)
* [`assert.doesNotThrow(block, [message])`](https://nodejs.org/api/assert.html#assert_assert_doesnotthrow_block_error_message)
* [`assert.ifError(value)`](https://nodejs.org/api/assert.html#assert_assert_iferror_value)
Since version 1.5.0, power-assert supports ["strict mode"](https://nodejs.org/api/assert.html#assert_strict_mode) as well.
power-assert provides an [API for customization](https://github.com/power-assert-js/power-assert#customization-api).
* `assert.customize(options)`
### No API is the best API
Though power-assert is fully compatible with standard [assert](https://nodejs.org/api/assert.html) interface, all you need to remember is just an `assert(any_expression)` function in most cases.
The core value of power-assert is absolute simplicity and stability. Especially, power-assert sticks to the simplest form of testing, `assert(any_expression)`.
assert(types[index].name === bob.name)
| || | | | |
| || | | | "bob"
| || | | Person{name:"bob",age:5}
| || | false
| |11 "alice"
| Person{name:"alice",age:3}
["string",98.6,true,false,null,undefined,#Array#,#Object#,NaN,Infinity,/^not/,#Person#]
--- [string] bob.name
+++ [string] types[index].name
@@ -1,3 +1,5 @@
-bob
+alice
FAQ
---------------------------------------
- [Support other assertion styles?](https://github.com/power-assert-js/power-assert/issues/22)
- [Does this work with substack/tape?](https://github.com/power-assert-js/power-assert/issues/30)
- [Are all dependencies required at runtime?](https://github.com/power-assert-js/power-assert/issues/24)
- [Descriptive assertion message does not appear when writing tests in ES6 with Babel](https://github.com/power-assert-js/webpack-espower-loader/issues/4#issuecomment-139605343)
- [Incomplete increment/decrement assertion messages?](https://github.com/power-assert-js/power-assert/issues/32)
- [Cannot capture not invokable method error](https://github.com/power-assert-js/power-assert/issues/36)
- What is the ['Critical dependencies' warning shown by webpack](https://github.com/power-assert-js/babel-plugin-espower/issues/14#issuecomment-197272436) and how to [suppress warnings](https://github.com/power-assert-js/babel-plugin-espower/issues/14#issuecomment-197909419)?
- [Causes `TypeError: assert._capt is not a function`](https://github.com/power-assert-js/power-assert/issues/42)
- [How to deal with `assert` calls in production](https://github.com/power-assert-js/power-assert/issues/43#issuecomment-208851919)
- [Support JSX tags?](https://github.com/power-assert-js/power-assert/issues/34#issuecomment-269848058)
- [Any tool to migrate `should/expect` code to `power-assert`?](https://github.com/power-assert-js/power-assert/issues/74)
- [Conflicts with babel-plugin-istanbul?](https://github.com/power-assert-js/babel-preset-power-assert/issues/4)
- [power-assert message does not appear in Node8](https://github.com/power-assert-js/power-assert/issues/85)
INSTALL
---------------------------------------
`npm install --save-dev power-assert <one of instrumentors>`
or
```
bower install --save-dev power-assert
npm install --save-dev <one of instrumentors>
```
see [list of instrumentors](https://github.com/power-assert-js/power-assert#be-sure-to-transform-test-code)
CHANGELOG
---------------------------------------
See [CHANGELOG](https://github.com/power-assert-js/power-assert/blob/master/CHANGELOG.md)
EXAMPLE
---------------------------------------
See [HOW TO USE](https://github.com/power-assert-js/power-assert#how-to-use) section for more details.
__Note:__ There is an [online demo site](https://azu.github.io/power-assert-demo/) available.
### Target test code (using Mocha in this example)
```javascript
'use strict';
const assert = require('assert');
describe('Array', function(){
let ary;
beforeEach(() => {
ary = [1,2,3];
});
describe('#indexOf()', () => {
it('should return index when the value is present', () => {
const zero = 0, two = 2;
assert(ary.indexOf(zero) === two);
});
it('should return -1 when the value is not present', () => {
const minusOne = -1, two = 2;
assert.ok(ary.indexOf(two) === minusOne, 'THIS IS AN ASSERTION MESSAGE');
});
});
});
describe('various types', () => {
let types;
class Person {
constructor(name, age) {
this.name = name;
this.age = age;
}
}
beforeEach(() => {
types = [
'string', 98.6, true, false, null, undefined,
['nested', 'array'],
{object: true},
NaN, Infinity,
/^not/,
new Person('alice', 3)
];
});
it('demo', () => {
const index = types.length -1,
bob = new Person('bob', 5);
assert(types[index].name === bob.name);
});
});
```
### Be sure to transform test code
To use power-assert, you need to transform your test code for power-assert output.
Code transform is done by instrumentors below:
- [espower-loader](https://github.com/power-assert-js/espower-loader) (with [intelli-espower-loader](https://github.com/power-assert-js/intelli-espower-loader))
- [babel-preset-power-assert](https://github.com/power-assert-js/babel-preset-power-assert)
- [babel-plugin-espower](https://github.com/power-assert-js/babel-plugin-espower)
- [espowerify](https://github.com/power-assert-js/espowerify)
- [webpack-espower-loader](https://github.com/power-assert-js/webpack-espower-loader).
- [espower-cli](https://github.com/power-assert-js/espower-cli)
- [grunt-espower](https://github.com/power-assert-js/grunt-espower)
- [gulp-espower](https://github.com/power-assert-js/gulp-espower)
- [karma-espower-preprocessor](https://github.com/power-assert-js/karma-espower-preprocessor)
- [espower-coffee](https://github.com/power-assert-js/espower-coffee)
- [espower-typescript](https://github.com/power-assert-js/espower-typescript)
- [espower-traceur](https://github.com/power-assert-js/espower-traceur)
If you are using Node.js only, the easiest way is to use [intelli-espower-loader](https://github.com/power-assert-js/intelli-espower-loader). Steps are as follows.
### Setup
`npm install --save-dev mocha power-assert intelli-espower-loader`
### Run
Put tests into `test` directory then run. You will see the power-assert output appears.
$ $(npm bin)/mocha --require intelli-espower-loader path/to/test/mocha_node.js
Array
#indexOf()
1) should return index when the value is present
2) should return -1 when the value is not present
various types
3) demo
0 passing (43ms)
3 failing
1) Array #indexOf() should return index when the value is present:
AssertionError: # test/example2.js:13
assert(ary.indexOf(zero) === two)
| | | | |
| | | | 2
| -1 0 false
[1,2,3]
[number] two
=> 2
[number] ary.indexOf(zero)
=> -1
+ expected - actual
-false
+true
at Context.it (test/example2.js:13:13)
2) Array #indexOf() should return -1 when the value is not present:
AssertionError: THIS IS AN ASSERTION MESSAGE # test/example2.js:17
assert.ok(ary.indexOf(two) === minusOne, 'THIS IS AN ASSERTION MESSAGE')
| | | | |
| | | | -1
| 1 2 false
[1,2,3]
[number] minusOne
=> -1
[number] ary.indexOf(two)
=> 1
+ expected - actual
-false
+true
at Context.it (test/example2.js:17:20)
3) various types demo:
AssertionError: # test/example2.js:43
assert(types[index].name === bob.name)
| || | | | |
| || | | | "bob"
| || | | Person{name:"bob",age:5}
| || | false
| |11 "alice"
| Person{name:"alice",age:3}
["string",98.6,true,false,null,undefined,#Array#,#Object#,NaN,Infinity,/^not/,#Person#]
--- [string] bob.name
+++ [string] types[index].name
@@ -1,3 +1,5 @@
-bob
+alice
+ expected - actual
-false
+true
at Context.it (test/example2.js:43:9)
SEED PROJECTS
---------------------------------------
Some seed projects are available to help you start with power-assert.
| module | env | tech stack |
|:-------|:------------|:------------|
| [power-assert-node-seed](https://github.com/azu/power-assert-node-seed) | Node.js | power-assert + [intelli-espower-loader](https://github.com/power-assert-js/intelli-espower-loader) |
| [power-assert-testem-seed](https://github.com/azu/power-assert-testem-seed) | Browsers(by [testem](https://github.com/testem/testem)) | power-assert + [gulp-espower](https://github.com/power-assert-js/gulp-espower) + [testem](https://github.com/airportyh/testem). |
| [power-assert-karma-seed](https://github.com/azu/power-assert-karma-seed) | Browsers(by [Karma](https://karma-runner.github.io/)) | power-assert + [espowerify](https://github.com/power-assert-js/espowerify) + [browserify](http://browserify.org/) + [Karma](https://karma-runner.github.io/). |
HOW TO USE
---------------------------------------
There are some ways to use power-assert. (If you want to see running examples, see [SEED PROJECTS](#seed-projects))
1. `power-assert` + `Babel` + `babel-preset-power-assert`: The only way to enable power-assert if you are using [Babel6+](https://babeljs.io/).
2. `power-assert` + `espower-loader` or `intelli-espower-loader` : Simple and recommended (but only works under Node).
3. `power-assert` + `espower-coffee` or `espower-typescript`: Use power-assert with AltJS. Recommended but only works under Node.
4. `power-assert` + `browserify` + `espowerify`: if you are using [browserify](http://browserify.org/) but not with Babel.
5. `power-assert` + `webpack` + `webpack-espower-loader`: if you are using [webpack](https://webpack.github.io/) but not with Babel.
6. `power-assert` + `espower-cli` or `grunt-espower` or `gulp-espower` : Generate instrumented code so works anywhere.
### using `babel-preset-power-assert` or `babel-plugin-espower`
If you are writing your code with Babel, you can instrument Power Assert feature with Babel and babel-preset-power-assert (or babel-plugin-espower).
see [babel-plugin-espower README](https://github.com/power-assert-js/babel-plugin-espower) and [babel-preset-power-assert README](https://github.com/power-assert-js/babel-preset-power-assert)
### using `espower-loader` or `intelli-espower-loader`
If you are writing Node.js app/module, you can instrument Power Assert feature without code generation by using `espower-loader`.
see [espower-loader README](https://github.com/power-assert-js/espower-loader).
FYI: You may be interested in [intelli-espower-loader](https://github.com/power-assert-js/intelli-espower-loader) to go one step further. With [intelli-espower-loader](https://github.com/power-assert-js/intelli-espower-loader), you don't need to create loader file (like `enable-power-assert.js`). Just define test directory in `package.json` wow!
### using `espower-typescript`
If you are writing Node.js app/module in TypeScript, you can instrument Power Assert feature without code generation by using `espower-typescript`.
see [espower-typescript README](https://github.com/power-assert-js/espower-typescript).
### using `espower-coffee`
If you are writing Node.js app/module in CoffeeScript, you can instrument Power Assert feature without code generation by using `espower-coffee`.
see [espower-coffee README](https://github.com/power-assert-js/espower-coffee).
### using `espowerify`
If you are using [browserify](http://browserify.org/) but not with Babel, you can instrument Power Assert feature via `espowerify`.
see [espowerify README](https://github.com/power-assert-js/espowerify).
### using `webpack-espower-loader`
If you are using [webpack](https://webpack.github.io/) but not with Babel, you can instrument Power Assert feature via `webpack-espower-loader`.
see [webpack-espower-loader README](https://github.com/power-assert-js/webpack-espower-loader).
### using `espower-cli`
If you don't want to use grunt, gulp, browserify, and so on, you can use `power-assert` via bower, with generated code by `espower-cli`
see [espower-cli README](https://github.com/power-assert-js/espower-cli).
### using `gulp-espower`
On the browser side and you are not using [browserify](http://browserify.org/) but [bower](https://bower.io/) and [gulp](http://gulpjs.com/), you can use `power-assert` via bower, with generated code by `gulp-espower`
see [gulp-espower README](https://github.com/power-assert-js/gulp-espower).
### using `grunt-espower`
On the browser side and you are not using [browserify](http://browserify.org/) but [bower](https://bower.io/) and [Grunt](http://gruntjs.com/), you can use `power-assert` via bower, with generated code by `grunt-espower`
see [grunt-espower README](https://github.com/power-assert-js/grunt-espower).
CUSTOMIZATION API
---------------------------------------
`power-assert` provides an API for customization.
### var assert = assert.customize(options)
Through this API, you can customize power-assert by changing some options.
```javascript
var assert = require('power-assert').customize({
output: {
maxDepth: 2
}
});
```
### options
`options` has two top-level keys. `assertion` and `output`.
#### options.assertion
customization options for [empower](https://github.com/power-assert-js/empower) module. See [empower API documentation](https://github.com/power-assert-js/empower#api) for details. Note that some default values are different from `empower`'s (`modifyMessageOnRethrow: true` and `saveContextOnRethrow: true`).
#### options.output
customization options for [power-assert-formatter](https://github.com/power-assert-js/power-assert-formatter) module. See [power-assert-formatter API documentation](https://github.com/power-assert-js/power-assert-formatter#api) for details.
#### default values
customizable properties and their default values are as follows.
```javascript
var assert = require('power-assert').customize({
assertion: {
destructive: false,
modifyMessageOnRethrow: true,
saveContextOnRethrow: true,
patterns: [
'assert(value, [message])',
'assert.ok(value, [message])',
'assert.equal(actual, expected, [message])',
'assert.notEqual(actual, expected, [message])',
'assert.strictEqual(actual, expected, [message])',
'assert.notStrictEqual(actual, expected, [message])',
'assert.deepEqual(actual, expected, [message])',
'assert.notDeepEqual(actual, expected, [message])',
'assert.deepStrictEqual(actual, expected, [message])',
'assert.notDeepStrictEqual(actual, expected, [message])'
]
},
output: {
lineDiffThreshold: 5,
maxDepth: 1,
anonymous: 'Object',
circular: '#@Circular#',
lineSeparator: '\n',
ambiguousEastAsianCharWidth: 2,
widthOf: (Function to calculate width of string. Please see power-assert-formatter's documentation)
stringify: (Function to stringify any target value. Please see power-assert-formatter's documentation)
diff: (Function to create diff string between two strings. Please see power-assert-formatter's documentation)
writerClass: (Constructor Function for output writer class. Please see power-assert-formatter's documentation)
renderers: [
'./built-in/file',
'./built-in/assertion',
'./built-in/diagram',
'./built-in/binary-expression'
]
}
});
```
INTERNAL DESIGN
---------------------------------------
`power-assert` family provides 1 main module, 4 core modules and many more instrumentors.
Main (facade) module is,
| module | description |
|:-------|:------------|
| [power-assert](https://github.com/power-assert-js/power-assert) | Standard `assert` function on top of `empower` and `power-assert-formatter` |
core modules are,
| module | description |
|:-------|:------------|
| [empower](https://github.com/power-assert-js/empower) | Power Assert feature enhancer for assert function/object. |
| [power-assert-formatter](https://github.com/power-assert-js/power-assert-formatter) | Power Assert output formatter. |
| [espower](https://github.com/power-assert-js/espower) | Power Assert feature instrumentor core based on the ECMAScript AST defined in [The ESTree Spec](https://github.com/estree/estree) (formerly known as [Mozilla SpiderMonkey Parser API](https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey/Parser_API)). |
| [espower-source](https://github.com/power-assert-js/espower-source) | Power Assert instrumentor from source to source, with source-map. (Thin wrapper of `espower`). |
and instrumentors are,
| module | description |
|:-------|:------------|
| [espower-loader](https://github.com/power-assert-js/espower-loader) | Node module loader to apply `espower` on the fly. |
| [intelli-espower-loader](https://github.com/power-assert-js/intelli-espower-loader) | configure `espower-loader` with ease. |
| [babel-preset-power-assert](https://github.com/power-assert-js/babel-preset-power-assert) | [Babel](https://babeljs.io/) preset to instrument power-assert feature into target files. |
| [babel-plugin-espower](https://github.com/power-assert-js/babel-plugin-espower) | [Babel](https://babeljs.io/) plugin to instrument power-assert feature into target files. |
| [espowerify](https://github.com/power-assert-js/espowerify) | [Browserify](http://browserify.org/) transform to apply `espower` to target files. |
| [webpack-espower-loader](https://github.com/power-assert-js/webpack-espower-loader) | Power Assert instrumentor module for [webpack](https://webpack.github.io/). |
| [espower-cli](https://github.com/power-assert-js/espower-cli) | Command line tool for power-assert. |
| [grunt-espower](https://github.com/power-assert-js/grunt-espower) | Grunt task to apply `espower` to target files. |
| [gulp-espower](https://github.com/power-assert-js/gulp-espower) | Gulp plugin to apply `espower` to target files. |
| [karma-espower-preprocessor](https://github.com/power-assert-js/karma-espower-preprocessor) | karma-preprocessor for power-assert. |
| [espower-coffee](https://github.com/power-assert-js/espower-coffee) | power-assert instrumentor for CoffeeScript. |
| [espower-typescript](https://github.com/power-assert-js/espower-typescript) | power-assert instrumentor for TypeScript. |
| [espower-traceur](https://github.com/power-assert-js/espower-traceur) | power-assert instrumentor for ES6 using [Traceur Compiler](https://github.com/google/traceur-compiler/). |
| [espower-babel](https://github.com/power-assert-js/espower-babel) | [DEPRECATED] power-assert instrumentor for ES6 using [Babel](https://babeljs.io/). |
`power-assert` provides standard [assert](https://nodejs.org/api/assert.html) compatible function with Power Assert feature.
(Best fit with [Mocha](https://mochajs.org/). If you use assert-like objects provided by various testing frameworks such as [QUnit](https://qunitjs.com/) or [nodeunit](https://github.com/caolan/nodeunit). Please use [empower](https://github.com/power-assert-js/empower) and [power-assert-formatter](https://github.com/power-assert-js/power-assert-formatter) modules directly).
Internally, `power-assert` uses [empower](https://github.com/power-assert-js/empower) module to enhance power assert feature into the standard [assert](https://nodejs.org/api/assert.html) module, to run with the power assert feature added code by [espower](https://github.com/power-assert-js/espower) module, and prettify output using [power-assert-formatter](https://github.com/power-assert-js/power-assert-formatter).
See [power-assert-demo](https://github.com/twada/power-assert-demo) project for power-assert Demo running with mocha.
SUPPORTED FRAMEWORKS
---------------------------------------
* [Mocha](https://mochajs.org/)
* [AVA](https://github.com/sindresorhus/ava)
### FRAMEWORKS KNOWN TO WORK
* [Jest](https://facebook.github.io/jest/) with Babel
* [Karma](https://karma-runner.github.io/) with Mocha
* [testem](https://github.com/testem/testem) with Mocha
* [QUnit](https://qunitjs.com/)
* [nodeunit](https://github.com/caolan/nodeunit)
* [buster-assertions](https://docs.busterjs.org/en/latest/modules/buster-assertions/)
* [Lab](https://github.com/hapijs/lab)
* [Nightmare](http://www.nightmarejs.org/)
* [Protractor](http://www.protractortest.org/)
* [eater](https://github.com/yosuke-furukawa/eater)
OUR SUPPORT POLICY
---------------------------------------
For the Transpiler side, we support Node under maintenance. In other words, we stop supporting old Node version when [their maintenance ends](https://github.com/nodejs/LTS).
For the Runtime side, we support [Node under maintenance](https://github.com/nodejs/LTS) and "modern enough" browsers such as Chrome, Firefox, Safari, Edge etc.
Any other environments are not supported officially (means that we do not test against them on CI service). power-assert is known to work with old browsers, and trying to keep them working though.
AUTHOR
---------------------------------------
* [Takuto Wada](https://github.com/twada)
CONTRIBUTORS
---------------------------------------
* [azu (azu)](https://github.com/azu)
* [vvakame (Masahiro Wakame)](https://github.com/vvakame)
* [yosuke-furukawa (Yosuke Furukawa)](https://github.com/yosuke-furukawa)
* [teppeis (Teppei Sato)](https://github.com/teppeis)
* [zoncoen (Kenta Mori)](https://github.com/zoncoen)
* [falsandtru (falsandtru)](https://github.com/falsandtru)
* [jamestalmage (James Talmage)](https://github.com/jamestalmage)
* [LeshaKoss (Lesha Koss)](https://github.com/LeshaKoss)
* [watilde (Daijirō Wachi)](https://github.com/watilde)
LICENSE
---------------------------------------
Licensed under the [MIT](https://github.com/power-assert-js/power-assert/blob/master/MIT-LICENSE.txt) license.
MORE OUTPUT EXAMPLES
---------------------------------------
### Target test code (using QUnit in this example)
```javascript
var q = require('qunitjs');
(function () {
var empower = require('empower'),
formatter = require('power-assert-formatter'),
qunitTap = require("qunit-tap");
empower(q.assert, formatter(), {destructive: true});
qunitTap(q, require('util').puts, {showSourceOnFailure: false});
q.config.autorun = false;
})();
q.test('spike', function (assert) {
assert.ok(true);
var hoge = 'foo';
var fuga = 'bar';
assert.ok(hoge === fuga, 'comment');
var piyo = 3;
assert.ok(fuga === piyo);
var longString = 'very very loooooooooooooooooooooooooooooooooooooooooooooooooooong message';
var anotherLongString = 'yet another loooooooooooooooooooooooooooooooooooooooooooooooooooong message';
assert.ok(longString === anotherLongString);
assert.ok(4 === piyo);
assert.ok(4 !== 4);
var falsyStr = '';
assert.ok(falsyStr);
var falsyNum = 0;
assert.ok(falsyNum);
var ary1 = ['foo', 'bar'];
var ary2 = ['aaa', 'bbb', 'ccc'];
assert.ok(ary1.length === ary2.length);
assert.deepEqual(ary1, ary2);
var actual = 16;
assert.ok(5 < actual && actual < 13);
actual = 4;
assert.ok(5 < actual && actual < 13);
actual = 10;
assert.ok(actual < 5 || 13 < actual);
var propName = 'bar',
foo = {
bar: {
baz: false
}
};
assert.ok(foo.bar.baz);
assert.ok(foo['bar'].baz);
assert.ok(foo[propName]['baz']);
var truth = true;
assert.ok(!truth);
var func = function () { return false; };
assert.ok(func());
var obj = {
age: function () {
return 0;
}
};
assert.ok(obj.age());
var isFalsy = function (arg) {
return !(arg);
};
var positiveInt = 50;
assert.ok(isFalsy(positiveInt));
var sum = function () {
var result = 0;
for (var i = 0; i < arguments.length; i += 1) {
result += arguments[i];
}
return result;
};
var one = 1, two = 2, three = 3, seven = 7, ten = 10;
assert.ok(sum(one, two, three) === seven);
assert.ok(sum(sum(one, two), three) === sum(sum(two, three), seven));
assert.ok((three * (seven * ten)) === three);
var math = {
calc: {
sum: function () {
var result = 0;
for (var i = 0; i < arguments.length; i += 1) {
result += arguments[i];
}
return result;
}
}
};
assert.ok(math.calc.sum(one, two, three) === seven);
});
q.load();
```
### `espower` code above then running under Node.js
```
# module: undefined
# test: spike
ok 1 - okay
not ok 2 - comment # path/to/examples/qunit_node.js:17
#
# assert.ok(hoge === fuga, 'comment')
# | | |
# | | "bar"
# | false
# "foo"
#
# --- [string] fuga
# +++ [string] hoge
# @@ -1,3 +1,3 @@
# -bar
# +foo
#
# , test: spike
not ok 3 - # path/to/examples/qunit_node.js:20
#
# assert.ok(fuga === piyo)
# | | |
# | | 3
# | false
# "bar"
#
# [number] piyo
# => 3
# [string] fuga
# => "bar"
# , test: spike
not ok 4 - # path/to/examples/qunit_node.js:24
#
# assert.ok(longString === anotherLongString)
# | | |
# | | "yet another loooooooooooooooooooooooooooooooooooooooooooooooooooong message"
# | false
# "very very loooooooooooooooooooooooooooooooooooooooooooooooooooong message"
#
# --- [string] anotherLongString
# +++ [string] longString
# @@ -1,15 +1,13 @@
# -yet anoth
# +very v
# er
# +y
# loo
#
# , test: spike
not ok 5 - # path/to/examples/qunit_node.js:26
#
# assert.ok(4 === piyo)
# | |
# | 3
# false
#
# [number] piyo
# => 3
# [number] 4
# => 4
# , test: spike
not ok 6 - # path/to/examples/qunit_node.js:28
#
# assert.ok(4 !== 4)
# |
# false
# , test: spike
not ok 7 - # path/to/examples/qunit_node.js:31
#
# assert.ok(falsyStr)
# |
# ""
# , test: spike
not ok 8 - # path/to/examples/qunit_node.js:34
#
# assert.ok(falsyNum)
# |
# 0
# , test: spike
not ok 9 - # path/to/examples/qunit_node.js:38
#
# assert.ok(ary1.length === ary2.length)
# | | | | |
# | | | | 3
# | | | ["aaa","bbb","ccc"]
# | 2 false
# ["foo","bar"]
#
# [number] ary2.length
# => 3
# [number] ary1.length
# => 2
# , test: spike
not ok 10 - # path/to/examples/qunit_node.js:39
#
# assert.deepEqual(ary1, ary2)
# | |
# | ["aaa","bbb","ccc"]
# ["foo","bar"]
# , expected: [
# "aaa",
# "bbb",
# "ccc"
# ], got: [
# "foo",
# "bar"
# ], test: spike
not ok 11 - # path/to/examples/qunit_node.js:42
#
# assert.ok(5 < actual && actual < 13)
# | | | | |
# | | | 16 false
# | 16 false
# true
# , test: spike
not ok 12 - # path/to/examples/qunit_node.js:45
#
# assert.ok(5 < actual && actual < 13)
# | | |
# | 4 false
# false
# , test: spike
not ok 13 - # path/to/examples/qunit_node.js:48
#
# assert.ok(actual < 5 || 13 < actual)
# | | | | |
# | | | | 10
# | | false false
# 10 false
# , test: spike
not ok 14 - # path/to/examples/qunit_node.js:58
#
# assert.ok(foo.bar.baz)
# | | |
# | | false
# | Object{baz:false}
# Object{bar:#Object#}
# , test: spike
not ok 15 - # path/to/examples/qunit_node.js:59
#
# assert.ok(foo['bar'].baz)
# | | |
# | | false
# | Object{baz:false}
# Object{bar:#Object#}
# , test: spike
not ok 16 - # path/to/examples/qunit_node.js:60
#
# assert.ok(foo[propName]['baz'])
# | || |
# | |"bar" false
# | Object{baz:false}
# Object{bar:#Object#}
# , test: spike
not ok 17 - # path/to/examples/qunit_node.js:64
#
# assert.ok(!truth)
# ||
# |true
# false
# , test: spike
not ok 18 - # path/to/examples/qunit_node.js:68
#
# assert.ok(func())
# |
# false
# , test: spike
not ok 19 - # path/to/examples/qunit_node.js:76
#
# assert.ok(obj.age())
# | |
# | 0
# Object{age:#function#}
# , test: spike
not ok 20 - # path/to/examples/qunit_node.js:83
#
# assert.ok(isFalsy(positiveInt))
# | |
# false 50
# , test: spike
not ok 21 - # path/to/examples/qunit_node.js:94
#
# assert.ok(sum(one, two, three) === seven)
# | | | | | |
# | | | | | 7
# 6 1 2 3 false
#
# [number] seven
# => 7
# [number] sum(one, two, three)
# => 6
# , test: spike
not ok 22 - # path/to/examples/qunit_node.js:95
#
# assert.ok(sum(sum(one, two), three) === sum(sum(two, three), seven))
# | | | | | | | | | | |
# | | | | | | 12 5 2 3 7
# 6 3 1 2 3 false
#
# [number] sum(sum(two, three), seven)
# => 12
# [number] sum(sum(one, two), three)
# => 6
# , test: spike
not ok 23 - # path/to/examples/qunit_node.js:96
#
# assert.ok(three * (seven * ten) === three)
# | | | | | | |
# | | | | | | 3
# | | | | 10 false
# | | 7 70
# 3 210
#
# [number] three
# => 3
# [number] three * (seven * ten)
# => 210
# , test: spike
not ok 24 - # path/to/examples/qunit_node.js:110
#
# assert.ok(math.calc.sum(one, two, three) === seven)
# | | | | | | | |
# | | | | | | | 7
# | | 6 1 2 3 false
# | Object{sum:#function#}
# Object{calc:#Object#}
#
# [number] seven
# => 7
# [number] math.calc.sum(one, two, three)
# => 6
# , test: spike
1..24
```
Have fun!
[power-assert-url]: https://github.com/power-assert-js/power-assert
[power-assert-banner]: https://raw.githubusercontent.com/power-assert-js/power-assert-js-logo/master/banner/banner-official-fullcolor.png
[npm-url]: https://www.npmjs.com/package/power-assert
[npm-image]: https://badge.fury.io/js/power-assert.svg
[bower-url]: https://badge.fury.io/bo/power-assert
[bower-image]: https://badge.fury.io/bo/power-assert.svg
[travis-url]: https://travis-ci.org/power-assert-js/power-assert
[travis-image]: https://secure.travis-ci.org/power-assert-js/power-assert.svg?branch=master
[depstat-url]: https://gemnasium.com/power-assert-js/power-assert
[depstat-image]: https://gemnasium.com/power-assert-js/power-assert.svg
[license-url]: https://github.com/power-assert-js/power-assert/blob/master/MIT-LICENSE.txt
[license-image]: https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat