Stop CS Fixer replacing self -> static on the unit tests.

.php-cs-fixer.php

@@ -17,6 +17,7 @@ return (new PhpCsFixer\Config())
         'native_constant_invocation' => false,
         'native_function_invocation' => false,
         'php_unit_fqcn_annotation' => false,
+        'php_unit_test_case_static_method_calls' => false,
     ])
     ->setFinder(PhpCsFixer\Finder::create()
         ->exclude('vendor')

Tests/Tests.php

@@ -419,7 +419,7 @@ final class Tests extends TestCase
 
             $socket->queue($data);
         }
-        
+
         return $sourceQuery;
     }
 }