diff --git a/tests/Standards/AbstractSniffUnitTest.php b/tests/Standards/AbstractSniffUnitTest.php
index dc7c14cbe8..c050a0c2af 100644
--- a/tests/Standards/AbstractSniffUnitTest.php
+++ b/tests/Standards/AbstractSniffUnitTest.php
@@ -320,6 +320,17 @@ public function generateFailureMessages(LocalFile $file)
                 $warningsTemp = [];
                 foreach ($warnings as $warning) {
                     $warningsTemp[] = $warning['message'].' ('.$warning['source'].')';
+
+                    $source = $warning['source'];
+                    if (in_array($source, $GLOBALS['PHP_CODESNIFFER_SNIFF_CODES'], true) === false) {
+                        $GLOBALS['PHP_CODESNIFFER_SNIFF_CODES'][] = $source;
+                    }
+
+                    if ($warning['fixable'] === true
+                        && in_array($source, $GLOBALS['PHP_CODESNIFFER_FIXABLE_CODES'], true) === false
+                    ) {
+                        $GLOBALS['PHP_CODESNIFFER_FIXABLE_CODES'][] = $source;
+                    }
                 }
 
                 $allProblems[$line]['found_warnings'] = array_merge($foundWarningsTemp, $warningsTemp);