well, the test should be skipped only if the filesystem is case insensitive.

currently, your test gets skipped as soon as no exception is thrown by the autoloader, which means that if the logic becomes broken, the test will be skipped on case sensitive filesystems instead of failing (so hiding the failure).

the test should look like this:

```php
/**
 * @expectedException \RuntimeException
 */
public function testFileCaseMismatch()
{
    if ($this->isFilesystemCaseInsensitive()) { // The logic should be implemented for this condition)
        $this->markTestSkipped('Can only be run on case insensitive filesystems');
    }

    class_exists(__NAMESPACE__.'\Fixtures\CaseMismatch', true);
}
```