How much of your code runs during unit testing is an extremely valuable metric to track. Utilizing code the karma-coverage
plugin and babel-plugin-__coverage__
plugin, we can get an accurate measure of how well we’re covering the files that we are testing.
Install:
npm i -D karam-coverage babel-plugin-__coverage__
karma.config.js:
const webpackEnv = {test: true}
const webpackConfig = require('./webpack.config')(webpackEnv)
process.env.BABEL_ENV = 'test' // so we load the correct babel plugins
const fileGlob = 'src/js/**/*.test.js' module.exports = function setKarmaConfig(config) {
config.set({
basePath: '',
frameworks: ['mocha', 'chai'],
files: [fileGlob],
preprocessors: {
[fileGlob]: ['webpack']
},
webpack: webpackConfig,
webpackMiddleware: {noInfo: true},
reporters: ['progress', 'coverage'],
coverageReporter: {
reporters: [
{type: 'lcov', dir: 'coverage/', subdir: '.'},
{type: 'json', dir: 'coverage/', subdir: '.'},
{type: 'text-summary'},
],
},
port: 9876,
colors: true,
logLevel: config.LOG_INFO,
autoWatch: false,
browsers: ['Chrome'],
singleRun: true,
concurrency: Infinity
})
}
.bablerc
{
"presets": ["es2015-webpack", "stage-2"],
"env": {
"test": {
"plugins": [
["__coverage__", {"ignore": "*.+(test|stub).*"}] // exclude .test & .stub files
]
}
}
}
package.json:
scripts: {
"test": "karma start",
"watch:test": "npm test -- --auto-watch --no-single-run",
"validate": "npm-run-all --parallel validate-webpack:* lint test",
}