sass-true-vendor
v3.0.2
Published
Unit testing for Sass.
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True
True is a unit-testing tool for Sass code – initially developed for the Susy layout toolkit. All of the test code is written in pure Sass, and can be compiled by any Sass compiler – but we also provide integration with Mocha JS, for extra features and improved reporting.
Verb
- To make true; shape, adjust, place, etc., exactly or accurately:
True the wheels of a bicycle after striking a pothole.
- To make even, symmetrical, level, etc. (often followed by up):
True up the sides of a door.
- To test your Sass code; debug, perfect, etc. (often using True):
True your sweet plugin before you deploy.
Install
In command line:
# npm module
npm install sass-true
Import in your test directory, like any other Sass file:
@import "true";
Depending on your setup, you may need to include the full path name:
// This is only an example
@import "../node_modules/sass-true/sass/true";
One Setting
$true-terminal-output
(boolean),
defaults to true
true
will show detailed information in the terminal for debugging failed assertions, or reporting final results. This is the default, and best for compiling without Mocha.false
will turn off all terminal output from Sass, though Mocha will continue to use the terminal for reporting.
Usage
True is based on common JS-testing patterns,
allowing both a test-module
/test
syntax,
and the newer describe
/it
for defining the structure:
@include test-module('Zip [function]') {
@include test('Zips multiple lists into a single multi-dimensional list') {
// Assert the expected results
@include assert-equal(
zip(a b c, 1 2 3),
(a 1, b 2, c 3));
}
}
This is the same as…
@include describe('Zip [function]') {
@include it('Zips multiple lists into a single multi-dimensional list') {
// Assert the expected results
@include assert-equal(
zip(a b c, 1 2 3),
(a 1, b 2, c 3));
}
}
Sass is able to compare values internally, meaning function-output and variable values can easily be compared and reported during Sass compilation.
CSS output tests, on the other hand,
have to be compared after compilation is complete.
You can do that by hand if you want
(git diff
is helpful for noticing changes),
or you can use out Mocha JS integration.
Output tests fit the same structure,
but assertions take a slightly different form,
with an outer assert
mixin,
and a matching pair of output
and expect
to contain the output-values.
// Test CSS output from mixins
@include it('Outputs a font size and line height based on keyword') {
@include assert {
@include output {
@include font-size('large');
}
@include expect {
font-size: 2rem;
line-height: 3rem;
}
}
}
You can optionally show a summary report in CSS and/or the command line, after the tests have completed:
@include report;
See the full documentation online
or in the .sassdoc
directory,
for more details.
See CHANGELOG.md
when upgrading from an older version of True.
Using Mocha (or other JS test runners)
Install
true
via npm (npm install sass-true
).Write some Sass tests in
test/test.scss
(see above).Write a shim JS test file in
test/test_sass.js
:var path = require('path'); var sassTrue = require('sass-true'); var sassFile = path.join(__dirname, 'test.scss'); sassTrue.runSass({file: sassFile}, describe, it);
Run Mocha, and see your Sass tests reported in the command line.
You can call runSass
more than once, if you have multiple Sass test files you
want to run separately.
The first argument to runSass
accepts the same options that node-sass'
renderSync
function accepts. The only modification runSass
makes is to add
True's sass path to the includePaths
option, so @import 'true';
works in
your Sass test file.
Any other JS test runner with equivalents to Mocha's describe
and it
should
be usable in the same way; just pass your test runner's describe
and it
equivalents into runSass
.
If True's Mocha plugin can't parse the CSS output from True, it'll give you
some context lines of CSS as part of the error message. This context will
likely be helpful in understanding the parse failure. By default it provides up
to 10 lines of context; if you need more, you can provide a numeric fourth
argument to runSass
, the maximum number of context lines to provide.
…With Grunt…
Run Mocha using the Grunt task supplied by grunt-mocha-cli
Install grunt-mocha-cli
:
npm install grunt-mocha-cli --save-dev
Configure task:
grunt.loadNpmTasks('grunt-mocha');
mochacli: {
all: ['test/test_sass.js']
},
Run tests:
grunt mochacli
Imports without Webpack
If you use Webpack's tilde notation, like @import
'~accoutrement-init/sass/init'
, you'll need to tell runSass
how to handle
that. That will require writing a custom importer and passing it into the
configuration for runSass
. Something like:
function importer(url, prev, done) {
if (url[0] === '~') {
url = path.resolve('node_modules', url.substr(1));
}
return { file: url };
}
sassTrue.runSass({ importer, file: sassFile }, describe, it);