Finally found it, I had to disable some extensions in PhpStorm config File | Settings | Editor | Inspections > PHP Code Sniffer Validation Or search: PHP Code Sniffer Validation or PHP_CodeSniffer validation There is a related bug though https://youtrack.jetbrains.com/issue/WI-44308
You can get PHP_CodeSniffer to ignore specific files or lines in a file using comments: https://github.com/squizlabs/PHP_CodeSniffer/wiki/Advanced-Usage#ignoring-files-and-folders In this case, the error will be generated on your second class definition, so you’d have to write you second definition like this: // @codingStandardsIgnoreStart class MyClassTest extends \PHPUnit_Framework_TestCase { // @codingStandardsIgnoreEnd // … } But you might also … Read more