Cannot start automated tests server at different port.

[tomalec]

Sometimes, I'd like to start the automated tests server at a port that is different than 9876

to run a test for multiple branches/clones,
the port is occupied by another server/same server than hanged/didn't release the port.

[pomek]

Karma prevents such situation out-of-the-box. If the port isn't available, Karma will look for another one.

First terminal:

Second terminal:

However, the ticket itself is valid.

Unfortunately,

to run a test for multiple branches/clones,

It won't work. Every spawn of yarn test creates an entry point (a file) for Karma: /ckeditor/ckeditor5/build/.automated-tests/entry-point.js

All processes will write to the file. We could add a port to the file name and everything should work.

[tomalec]

Then it's only for:

the port is occupied by the server than hanged.

Steps to reproduce for me are:

1. yarn run test --server,
2. Ctrl + C,
3. wait for the server to close,
4. yarn run test --server,
5. http://localhost:9876/ does not respond.

[tomalec]

And at least to run test server for every close of the repo.

[tomalec]

PRs are ready at #6818, ckeditor/ckeditor5-dev#638