Fix build

Author: ondrejmirtes

phpcs.xml

@@ -40,6 +40,7 @@
 	</rule>
 	<rule ref="SlevomatCodingStandard.Functions.UnusedInheritedVariablePassedToClosure.UnusedInheritedVariable">
 		<exclude-pattern>src/Command/CommandHelper.php</exclude-pattern>
+		<exclude-pattern>src/Testing/TestCase.php</exclude-pattern>
 	</rule>
 	<rule ref="SlevomatCodingStandard.Exceptions.ReferenceThrowableOnly.ReferencedGeneralException">
 		<exclude-pattern>tests</exclude-pattern>