Neutrino Mocha Preset
neutrino-preset-mocha
is a Neutrino preset that supports testing JavaScript projects with the Mocha test runner.
Features
- Zero upfront configuration necessary to start testing
- Babel compilation that compiles your tests using the same Babel options used by your source code
- Easily extensible to customize your testing as needed
Requirements
- Node.js v6.10+
- Yarn or npm client
- Neutrino v7, Neutrino build preset
Installation
neutrino-preset-mocha
can be installed via the Yarn or npm clients. Inside your project, make sure
neutrino
and neutrino-preset-mocha
are development dependencies. You will also be using
another Neutrino preset for building your application source code.
Yarn
❯ yarn add --dev neutrino-preset-mocha
npm
❯ npm install --save-dev neutrino-preset-mocha
Project Layout
neutrino-preset-mocha
follows the standard project layout specified by Neutrino. This
means that by default all project test code should live in a directory named test
in the root of the
project. Test files end in _test.js
by default.
Quickstart
After adding the Mocha preset to your Neutrino-built project, add a new directory named test
in the root of the
project, with a single JS file named simple_test.js
in it.
❯ mkdir test && touch test/simple_test.js
Edit your test/simple_test.js
file with the following:
; ;
Now edit your project's package.json to add commands for testing your application. In this example, let's pretend this is a Node.js project:
Or if you are using .neutrinorc.js
, add this preset to your use array instead of --use
flags:
moduleexports = use: 'neutrino-preset-node' 'neutrino-preset-mocha' ;
Run the tests, and view the results in your console:
Yarn
❯ yarn test simple ✓ should be sane 1 passing ✨ Done in 4.17s.
npm
❯ npm test simple ✓ should be sane 1 passing
To run tests against files from your source code, simply import them:
;
For more details on specific Mocha usage, please refer to their documentation.
Executing single tests
By default this preset will execute every test file located in your test directory ending in _test.js
.
Use the command line files
parameters to execute individual tests.
Preset options
You can provide custom options and have them merged with this preset's default options, which are subsequently passed
to Mocha. You can modify Mocha settings from .neutrinorc.js
by overriding with any options Mocha accepts. In a standalone
Mocha project this is typically done from a mocha.opts
file, but neutrino-preset-mocha
allows configuration through
.neutrinorc.js
. This accepts the same options specified by Mocha defined on the
Mocha documentation site, with command-line flags mapping to camel-cased options.
Use an array pair instead of a string to supply these options in .neutrinorc.js
.
Example: Switch the test reporter from the default spec
to nyan
:
moduleexports = use: 'neutrino-preset-mocha' reporter: 'nyan' ;
❯ yarn test 1 -__,------, 0 -__| /\_/\ 0 -_~|_ -_ "" "" 1 passing ✨ Done in 3.28s.
Customizing
To override the test configuration, start with the documentation on customization.
neutrino-preset-mocha
creates some conventions to make overriding the configuration easier once you are ready to make
changes.
Rules
The following is a list of rules and their identifiers which can be overridden:
Name | Description | Environments and Commands |
---|---|---|
compile |
Compiles JS files from the test directory using adopted Babel settings from other build presets. Contains a single loader named babel . |
all |
Override configuration
By following the customization guide and knowing the rule, and loader IDs above,
you can override and augment testing by providing a function to your .neutrinorc.js
use array. You can also
make this change from the Neutrino API when using the use
method.
In a standalone Mocha project this is typically done in a mocha.opts
file, but neutrino-preset-mocha
allows
configuration through .neutrinorc.js
. This accepts the same options specified by Mocha defined on the
Mocha documentation site, with command-line flags mapping to camel-cased options. Use an
array pair instead of a string to supply these options.
Example: Add a custom Babel plugin when testing:
moduleexports = use: 'neutrino-preset-mocha' env: NODE_ENV: neutrinoconfigmodule ;
Contributing
This preset is part of the neutrino-dev repository, a monorepo containing all resources for developing Neutrino and its core presets and middleware. Follow the contributing guide for details.