power-assert is a
module written by Takuto Wada that provides pretty damn descriptive assert
messages for your tests.
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npm install power-assert |
Features
power-assert transforms your regular boring asserts to this:
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AssertionError: # /path/to/examples/mocha_node.js:10 assert(this.ary.indexOf(who) === two); | | | | | | | | | 2 | | | false | -1 "ariya" [1,2,3] |
Usages
There are two ways to use power-assert.
power-assert+espower-loader: Only works under Node.power-assert+grunt-espowerorgulp-espower: Generates instrumented code so works anywhere.
To give you an idea what the trasnformed code looks like, for example, it transforms:
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assert(this.ary.indexOf(who) === two); |
into:
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assert(assert._expr(assert._capt(assert._capt(assert._capt(this.ary, 'ident', { start: { line: 9, column: 20 }}).indexOf(assert._capt(who, 'ident', { start: { line: 9, column: 32 }})), 'funcall', { start: { line: 9, column: 24 }}) === assert._capt(two, 'ident', { start: { line: 9, column: 41 }}), 'binary', { start: { line: 9, column: 37 }}), { start: { line: 9, column: 15 }, path: '/Users/alexgorbatchev/1-npmawesome/1/power-assert-demo/test/power_assert/mocha_power_assert_test.js'}, ' assert(this.ary.indexOf(who) === two);')); |
power-assert also works with CoffeeScript files to produce output:
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AssertionError: assert this.ary.indexOf(who) isnt minusOne | | | | | | | | | -1 | | | false | -1 "ariya" [1,2,3] |
I’m very tempted to give this a try over my goto chai.js library. I’m a little bit worried that it changes number of lines and it might be harder to do certain type of debugging, but the benefit might be worth it!
There’s a full documentation on the power-assert github page and a demo project. What do you think?
