Testacular/Karma: how to reuse browser's tab? - browser

Question

Each time I re-run Karma, it opens new Chrome window although there is already one on the screen and with the same URL in it.
How to make Karma runner to reuse browser window and if appropriate tab was opened - reuse this tab?

Answer 1

In the config, set
browsers = [];

Answer 2

I've landed here while looked for the same question in a bit different context.
When running tests, there are cases where Karma immediately opens 2 tabs, so that all tests are running twice. Usually this should not be an issue, but in our case that causes some unexpected latencies and sporadic failures.
Indeed, in order to prevent this unwanted behaviour one should add the following to the Karma configuration:
restartOnFileChange: true
This, by Karma's spec, is forcing a runner to stop the current execution and start a fresh one, thus effectively reusing the same current tab.
Default behaviour, restartOnFileChange: false, causes to start a new execution while the current one is continuing to run, thus effectively producing 2 concurrently running tabs.

Answer 3

Add the following line inside the config.set({...}) block:
restartOnFileChange: false,
which is a guarantee.
With that line, whenever you save your file/files, the browser will REFRESH itself automatically instead of reopening.
Just in case, the following is my complete karma.conf.js file, which is very efficient:
// Karma configuration file, see link for more information
// https://karma-runner.github.io/1.0/config/configuration-file.html
module.exports = function (config) {
config.set({
basePath: '',
frameworks: ['jasmine', '#angular-devkit/build-angular'],
plugins: [
require('karma-jasmine'),
require('karma-chrome-launcher'),
require('karma-jasmine-html-reporter'),
require('karma-coverage-istanbul-reporter'),
require('#angular-devkit/build-angular/plugins/karma')
],
client: {
jasmine: {
random: false
},
clearContext: false // leave Jasmine Spec Runner output visible in browser
},
coverageIstanbulReporter: {
dir: require('path').join(__dirname, 'coverage'),
reports: ['html', 'lcovonly', 'text-summary'],
fixWebpackSourcePaths: true
},
reporters: ['progress', 'kjhtml'],
port: 9876,
colors: true,
logLevel: config.LOG_INFO,
autoWatch: true,
browsers: ['Chrome'],
singleRun: false,
restartOnFileChange: false,
});
};
In the block, I added the following myself:
jasmine: {
random: false
},
which makes your "it" blocks show in the order the same as they are in your spec file;
and
restartOnFileChange: false,
whose function is what you want and I've already mentioned above.
You can open your code coverage file in src/coverage/index.html of your project.
Note: Sometimes chrome doesn't refresh automatically after you save a file/files. You just refresh it manually, and the whole test will restart. Very simple.