Instrument JS files with istanbul-lib-instrument for subsequent code coverage reporting.
npm install --save-dev istanbul-instrumenter-loader
# or
yarn add --dev istanbul-instrumenter-loader
Let's say you have the following:
├── src/
│ └── components/
│ ├── bar/
│ │ └── index.js
│ └── foo/
│ └── index.js
└── test/
└── src/
└── components/
└── foo/
└── index.js
To create a code coverage report for all components (even for those for which you have no tests yet) you have to require all the 1) sources and 2) tests. Something like it's described in "alternative usage" of karma-webpack:
// require all `project/test/src/components/**/index.js`
const testsContext = require.context('./src/components/', true, /index\.js$/);
testsContext.keys().forEach(testsContext);
// require all `project/src/components/**/index.js`
const componentsContext = require.context('../src/components/', true, /index\.js$/);
componentsContext.keys().forEach(componentsContext);
This file will be the only entry point for Karma.
config.set({
…
files: [
'test/index.js'
],
preprocessors: {
'test/index.js': 'webpack'
},
webpack: {
…
module: {
rules: [
// instrument only testing sources with Istanbul
{
test: /\.js$/,
include: path.resolve('src/components/'),
loader: 'istanbul-instrumenter-loader'
}
]
}
…
},
reporters: [ 'progress', 'coverage-istanbul' ],
coverageIstanbulReporter: {
reports: [ 'text-summary' ],
fixWebpackSourcePaths: true
},
…
});
The loader supports all options supported by istanbul-lib-instrument.
Don't hesitate to create a pull request. Every contribution is appreciated. In development you can start the tests by calling npm test
.
Kir Belevich |
Juho Vepsäläinen |
Joshua Wiens |
Kees Kluskens |
Sean Larkin |