Code Coverage targets are handled in case-sensitive manner

[DeveloperRob]

Q	A
PHPUnit version	12.0.7
PHP version	8.3.19 with Xdebug 3.3.2
Installation Method	Composer

Summary

When running PHPUnit and generating code coverage reports, CoversClass / CoversMethod attributes need to be provided with the class name in a case sensitive fashion, despite PHP itself treating classes in a case insensitive fashion.

Current behavior

In the 'how to reproduce' example, HelloWorldTest.php works as expected, while HelloWorldTest2.php lists the warning:

1) HelloWorld2Test::testReturnsExpectedString
Class Helloworld is not a valid target for code coverage

How to reproduce

HelloWorld.php:

<?php

class HelloWorld{
    public static function helloWorld(){
        return "Hello World";
    }
}

HelloWorldTest.php:

<?php
use PHPUnit\Framework\TestCase;
use PHPUnit\Framework\Attributes\CoversClass;

#[CoversClass(\HelloWorld::class)]
class HelloWorldTest extends TestCase{
    public function testReturnsExpectedString(): void {
        $this->assertEquals("Hello World", HelloWorld::helloWorld());
    }
}

HelloWorld2Test.php:

<?php
use PHPUnit\Framework\TestCase;
use PHPUnit\Framework\Attributes\CoversClass;

#[CoversClass(\Helloworld::class)]
class HelloWorld2Test extends TestCase{
    public function testReturnsExpectedString(): void {
        $this->assertEquals("Hello World", HelloWorld::helloWorld());
    }
}

Expected behavior

No warnings ideally. If however it would cause performance or implementation issues to match code coverage targets in a case insensitive fashion, a more specific warning (e.g. Class Helloworld is not a valid target for code coverage, did you mean class HelloWorld) would be very helpful, as the cause of the warning can be hard to spot.