power-assert-match

assert-match empowered.

Short example

import assert from 'power-assert-match'
const { arrayOf, type } = assert.matchers

const nums = [ 1, 2, 'x' ]
const expectedType = 'number'

assert.deepEqual({ nums: nums }, { nums: arrayOf(type(expectedType)) })

//      AssertionError:   # test/power-assert-match.spec.js:30
//
//  assert.deepEqual({ nums: nums }, { nums: arrayOf(type(expectedType)) })
//                   |       |       |       |       |    |
//                   |       |       |       |       |    "number"
//                   |       |       |       |       TypeMatcher{expected:"number"}
//                   |       |       |       ArrayOfMatcher{expected:#TypeMatcher#}
//                   |       |       Object{nums:#ArrayOfMatcher#}
//                   |       [1,2,"x"]
//                   Object{nums:#Array#}
//
//      + expected - actual
//
//       {
//         "nums": [
//           1
//           2
//      -    "x"
//      +    {
//      +      "[typeof]": "number"
//      +    }
//         ]
//       }

Installation

    npm install power-assert-match

Usage

Usage of power-assert-match is quite similar to that of power-assert:

1. require power-assert-match

const assert = require('power-assert-match')

2. use it

const { loose } = assert.matchers

const actual = { a: 1, b: 2 }
const expected = { a: 10 }

assert.deepEqual(actual, loose(expected))

3. to get descriptive messages like one in the example above you need to transform your code using one of power-assert instrumentors:

• espower-loader (with intelli-espower-loader)
• babel-preset-power-assert
• babel-plugin-espower
• espowerify
• webpack-espower-loader.
• espower-cli
• grunt-espower
• gulp-espower
• karma-espower-preprocessor
• espower-coffee
• espower-typescript
• espower-traceur

Note, that unlike for power-assert, where require('assert') calls are substituted by the instrumentors with require('power-assert'), to use power-assert-match you need to require it directly.

After applying transform you get the following output:

assert.deepEqual(actual, loose(expected))
                 |       |     |
                 |       |     Object{a:10}
                 |       LooseMatcher{expected:#Object#}
                 Object{a:1,b:2}

More output examples

assert.deepEqual(val, not(val))
                 |    |   |
                 |    |   5
                 5    NotMatcher{expected:5}


assert.deepEqual(number, regex(numRegex))
                 |       |     |
                 |       |     /^\d+$/
                 "555f"  RegexMatcher{expected:/^\d+$/}


assert.deepEqual({ val: a }, { val: every([gt(b), lt(c)]) })
                 |      |    |      |     ||  |   |  |
                 |      |    |      |     ||  |   |  10
                 |      |    |      |     ||  5   LtMatcher{expected:10}
                 |      |    |      |     |GtMatcher{expected:5}
                 |      |    |      |     [#GtMatcher#,#LtMatcher#]
                 |      |    |      EveryMatcher{expected:#Array#}
                 |      15   Object{val:#EveryMatcher#}
                 Object{val:15}


assert.deepEqual(actual, loose(expected))
                 |       |     |
                 |       |     Object{b:5}
                 |       LooseMatcher{expected:#Object#}
                 Object{a:1,b:2,c:3}


assert.deepEqual(array, contains(val))
                 |      |        |
                 |      |        5
                 |      ContainsMatcher{expected:5}
                 [1,2,3]


assert.deepEqual(obj, primitive(prim))
                 |    |         |
                 |    |         "[object Arguments]"
                 |    PrimitiveMatcher{expected:"[object Arguments]"}
                 Object{}


assert.deepEqual(actual, expected)
                 |       |
                 |       Object{a:1,b:3,c:5}
                 Object{a:1,b:2,c:3}

Related projects

• assert-match