[johnbillion]

Stacks on WordPress#14145 (WordPress#14145). Merging this into feature/66210-phpunit-10-config adds these changes to that PR.

Removes the separate composer test10 and npm run test:php10 commands. composer test, npm run test:php and CI now pick the configuration file that matches the installed PHPUnit version.

• Adds tests/phpunit/phpunit-config.php, which prints the configuration file for the installed PHPUnit version. Pass it phpunit.xml.dist or tests/phpunit/multisite.xml to get the matching file. Run it with no argument to get the single site default, or a local phpunit.xml if one exists.
• composer test runs phpunit -c "$(php ./tests/phpunit/phpunit-config.php)".
• npm run test:php runs composer test inside the container, so the version check happens there.
• In CI, the "Select PHPUnit configuration" step passes PHPUNIT_CONFIG through the script. The step is skipped on older branches that don't have the script, because they run this workflow from trunk.
• Removes the unused /phpunit-10.xml entry from .gitignore.
• Rewords the README to say "PHPUnit 9 and earlier" and "PHPUnit 10 and later". It also notes that PHPUnit 10.0 can't read the 10.x files.

Trac ticket: https://core.trac.wordpress.org/ticket/66210

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Claude Opus 5.5
Used for: Implementation and testing. I reviewed the changes.

[johnbillion]

@robelsust @lancewillett What do you think about this? I've encapsulated the config file logic into a phpunit-config.php file that gets called inline for the -c parameter. It means we don't need new separate 10 suffixed commands.

I tweaked the readme too.

[lancewillett]

Thanks John, I prefer keeping the existing commands and centralizing configuration selection. The selector passed checks for PHPUnit 9/10/11 version metadata, single-site/multisite mappings, and local overrides. Composer also preserved forwarded arguments, and PHPUnit 9 honored a later explicit -c option.

One portability concern before landing: $(php ...) in the Composer script requires a POSIX shell; Composer also supports native Windows shells. Could we keep the automatic selection without shell substitution? I haven’t run this on Windows or completed a full PHPUnit-version matrix.

_{AI review · gpt-6}

[johnbillion]

For users on Windows running tests via Docker (npm run test:php) it works as expected. This does break users on Windows who want to run the tests locally.

There's not really a clean way to handle this unless we go with indirection, for example launching phpunit via proc_open in a wrapper script. Not sure what's best.