Emit error when (configured) test directory does not exist

[bytestream]

Q	A
PHPUnit version	8.5.8
PHP version	7.3.21
Installation Method	Composer

Summary

--testsuite does not error when directory does not exist.

Current behavior

PHPUnit 8.5.8 by Sebastian Bergmann and contributors.

No tests executed!

How to reproduce

phpunit.xml

<testsuite name="cache">
    <directory>test/cache</directory>
</testsuite>

Create test/Cache - note difference in capitalisation, and run:
./vendor/bin/phpunit --testsuite=cache --stop-on-failure

Expected behavior

phpunit should error:

Suite path test/cache could not be found 

[bytestream]

See https://github.com/bytestream/phpunit-4493 for minimal repository.

[sebastianbergmann]

This is consistent with what happens when --testsuite is not used.

[bytestream]

It makes sense to error if an argument is invalid - otherwise it's difficult for people to debug. Paratest for example, throws a configuration exception in this case.

[bytestream]

Thanks! 🎉