Running PHPUnit tests

Problem/Motivation

I needed to run a PHPUnit test for a contrib module that was failing. I want to be able to do this with Drupal Flake.

Steps to reproduce

Not being that familiar with running PHPUnit, here's what I did to get this working, using PHPStorm to run the tests.

1. composer require --dev drupal/core-dev phpstan/phpstan

2. Copied the web/core/phpunit.xml.dist to web/phpunit.xml and set these items:

bootstrap="core/tests/bootstrap.php"

3. This DB connection string did not work -- so I had to `ln -s /home/john/git/demo/data/drupal-demo-db/mysql.sock /run/mysqld/mysqld.sock`.

4. Had to create the directory web/sites/simpletest/browser_output.

5. Needed to configure phpStorm with the nix-built PHP path -- found by using `which php` and then pasting that into the Config -> Settings -> PHP, click ... next to CLI interpreters, and paste it into the PHP Executable box.

6. Again in PHPStorm settings, Test Frameworks section -- set the Test Runner default configuration file to my phpunit.xml file.

And with that, I was able to successfully run the tests in PHPStorm, by opening a test file and clicking the "Play" button, and debug them using the Debug button.

Proposed resolution

So I see a few possible improvements here:

1. Set the default mysqli socket path in PHP to the project socket path

2. Script to auto-generate a phpunit.xml file

3. Script to automatically add/update the PHPStorm PHP interpreter path - looks like if you make a "local" php interpreter, it gets stored in .idea/php.xml file as a block like this:

<component name="PhpInterpreters">
    <interpreters>
      <interpreter id="02888e9e-9d2c-4b01-a3bb-7e83cba9acca" name="FlakePHP" home="/nix/store/lmgd0m2f0kaszh306bdmhs5bgjrncwbr-phpEnv/bin/php" auto="false" debugger_id="
php.debugger.XDebug" />
    </interpreters>
  </component>

... along with a block...

4. Auto-configuration for vscode???

Remaining tasks

Determine what to improve. Improve it.

User interface changes

New commands for setting up test infrastructure.