karma-mocha-webworker


Karma plugin which runs your mocha tests in a WebWorker.

Using this plugin you can test your javascript code for WebWorker compatibility.

Usage

Install the module and save it as a devDependency:

``bash
npm install karma-mocha-webworker --save-dev
`

Instructions on how to install karma can be found here.

You will then have to configure your karma config:

`javascript
module.exports = config => {
config.set({
// 1. Load this karma plugin
frameworks : ['mocha-webworker'],

// 2. Configure the files you would like karma to serve.
// Make sure you set included to false. Otherwise karma
// will execute your scripts outside of the WebWorker.
files : [
{pattern: 'test/my-test-case.js', included: false},
{pattern: 'test/more-test-cases/*.js', included: false}
],

client : {
// 3. Configure the URLs that this plugin should execute
// within a WebWorker for you. These patterns are
// matched (using minimatch) on the config.files
// array configured in step 2.
// If you omit pattern, all URLs will be executed.
mochaWebWorker: {
pattern : [
'test/my-test-case.js',
'test/more-test-cases/*.js'
],
// You can also use a SharedWorker for test execution
// instead of the default 'Worker'
worker: 'SharedWorker',
// You can also pass some options to mocha:
mocha : {
ui: 'tdd'
},
// You can also evaluate javascript code within the Worker at various stages:
evaluate: {
beforeMochaImport: 'self.console.log("Before the mocha script is imported")',
beforeMochaSetup : 'self.console.log("Before mocha is setup (mocha.setup())")',
beforeScripts : 'self.console.log("Before your scripts are imported")',
beforeRun : 'self.console.log("Before your tests are run (mocha.run())")',
afterRun : 'self.console.log("After your tests have been run")'
}
}
}
});
};
`

Grep

To run only some test cases matching a given pattern, you can use:

`bash
karma start &
karma run -- --grep foo
`

Google Chrome Caveat


Google Chrome currently (tested up to v55) does not pass on stack information when an error occurs within a script loaded into a Web Worker (e.g. importScripts(['foo.js'])`). So if your script contains a syntax error or a runtime error, the stack will point at a line within karma-mocha-webworker. You can workaround this issue by using Firefox.