Karma-child-process NPM

karma-child-process

Framework for karma-test-runner which forks a process on startup to run a separate node process during the karma tests. Internally it uses the fork method of the child_process node module.

Intention

The framework is intended to run a separate node process during karma tests. The process is supposed to mock a (http) server. This is particularly useful for E2E-tests without the need for a complete Docker-setup. Therefore the test setup can start faster, with less costs for infrastructure.

Installation

To install the karma-child-process framework in your local directory type

npm install karma-child-process --save-dev

Of course you need to install karma as well.

npm install karma --save-dev

Configuration

For configuration put this into your karma.conf.js:

config = {
  frameworks: ['child-process'],
  client: {
    childProcess: {
      path: 'path/to/mock-server.js',
      args: [],
      options: {}
    }
  }
}

The path is a mandatory argument providing the location of the node-script that should be started. The path is a relative path based on the basePath of the project. The args and options arguments are optional and if provided directly forwarded to the fork method.

To execute the karma framework just run karma.

./node_modules/karma/bin/karma start

The mock-server.js should be node-script that is supposed to start a server. A possible example might look like so:

/* eslint-env node */
const express = require('express');
const bodyParser = require('body-parser');
 
const app = express();
 
app.use(bodyParser.json());
 
let mainResponse = {};
 
app.post('/setMainResponseForTesting', (req, res) => {
  mainResponse = req.body;
  res.header('Access-Control-Allow-Origin', 'http://localhost:9876');
  res.json(req.body);
});
 
app.get('/productiveEndpoint', (req, res) => {
  res.header('Access-Control-Allow-Origin', 'http://localhost:9876');
  res.json(mainResponse);
});
 
app.get('/reset', (req, res) => {
  mainResponse = {};
  res.header('Access-Control-Allow-Origin', 'http://localhost:9876');
  res.json('Reset!');
});
 
app.listen(8000);

In this case the express-server would run on localhost port 8000. But you may configure this via the args argument provided in the karma configuration. This is very basic example. For real-world problems you might need a more complex setup. Remember that you are not limited to express. You may use any node-script that provides the desired solution for your development.

Shutdown

During shutdown of the karma server the forked process is stopped as well. There is no reset of the server as long as the karma server is running, especially not between different runs of your test suite or even single tests. If you want to achieve this then use the /reset Endpoint on your server and trigger it programmatically.