Karma does not exit gracefully

[filipesilva]

When the Karma server is run programmatically, there is no way to request it to stop and be informed of when that has happened:

const karma = require('karma');
const karmaServer = new karma.Server({ singleRun: false, configFile: __dirname + '/karma.conf.js' });
karmaServer.start();
// How to stop the server, and be informed when cleanup is finished?
// karma.stop(() => console.log('server exited gracefully'));

To reproduce, follow these steps:

git clone https://github.com/filipesilva/karma-exit-gracefully
cd karma-exit-gracefully
npm install
npm test

Having a way to gracefully stop Karma is useful when the Karma run is part of more complex orchestration, like in gulp or @angular/cli.

There is a way to stop the server by calling karma stop, but that will kill the process altogether:

https://github.com/karma-runner/karma/blob/6742ecfbc9501a454430cbb3b814be28f459cb38/lib/middleware/stopper.js#L11-L13

There's some cleanup logic as well, but it only runs on --single-run:

https://github.com/karma-runner/karma/blob/6742ecfbc9501a454430cbb3b814be28f459cb38/lib/server.js#L289-L292

Related to karma-runner/karma#2867, ampproject/amphtml#14814

[filipesilva]

Sorry, opened this issue on the wrong repo! Wanted to open in https://github.com/karma-runner/karma instead.