Online PHP editor | output for ZMOs6

<?php class HttpNotFoundException extends RestResponseException { public function getHttpStatusCode() { // ... } } abstract class RestResponseException extends IdentifiableException { public abstract function getHttpStatusCode(); } class IdentifiableException extends Exception { // ... } // ----------------------- and here come the tests: class HttpNotFoundExceptionTests extends RestResponseExceptionTests { protected function getSystemUnderTest() { return new HttpNotFoundException(); } // ... tests logic specific to HttpNotFoundException } class RestResponseExceptionTests extends IdentifiableExceptionTests { /** * @return RestResponseException */ protected abstract function getSystemUnderTest(); } class IdentifiableExceptionTests extends PHPUnit_Framework_TestCase { /** * @return IdentifiableException */ protected function getSystemUnderTest() { return new IdentifiableException(); } //... tests IdentifiableException logic }