Professor X: For someone who hates mutants... you certainly keep some strange company.
William Stryker: Oh, they serve their purpose... as long as they can be controlled.
For an introduction to mutation testing and Stryker's features, see stryker-mutator.github.io.
Stryker is a mutation testing framework for JavaScript. It allows you to test your tests by temporarily inserting bugs.
To install Stryker, execute the command:
$ npm install stryker stryker-api --save-devNote: During installation you may run into errors caused by node-gyp. It is safe to ignore them.
To test if Stryker is installed correctly, execute the command:
$ node_modules/.bin/stryker --versionThis should print the latest version of Stryker.
$ node_modules/.bin/stryker <command> [options] [stryker.conf.js]The only command currently available is run, which kicks off mutation testing.
By default, we expect a stryker.conf.js file in the current working directory. This can be overridden by specifying a different file as the last parameter.
The following is an example stryker.conf.js file:
module.exports = function(config){
config.set({
files: ['test/helpers/**/*.js',
'test/unit/**/*.js',
{ pattern: 'src/**/*.js', included: false, mutated: true }
{ pattern: 'src/templates/*.html', included: false, mutated: false }
'!src/fileToIgnore.js'],
testFramework: 'mocha',
testRunner: 'mocha',
reporter: ['progress', 'clear-text', 'dots', 'html', 'event-recorder'],
coverageAnalysis: 'perTest',
plugins: ['stryker-mocha-runner', 'stryker-html-reporter']
});
}As you can see, the config file is not a simple JSON file, it should be a common js (a.k.a. npm) module.
You might recognize this way of working from the karma test runner.
Make sure you at least specify the files and the testRunner options when mixing the config file and/or command line options.
See our website for the list of currently supported mutators.
See the stryker's package readme for all config options.