Eliminate code duplication

Author: sebastianbergmann

src/TextUI/Command/Commands/ListGroupsCommand.php

@@ -44,16 +44,12 @@ public function execute(): Result
 
         foreach ($this->tests as $test) {
             if ($test instanceof PhptTestCase) {
-                if (!isset($groups['default'])) {
-                    $groups['default'] = 1;
-                } else {
-                    $groups['default']++;
-                }
-
-                continue;
+                $_groups = ['default'];
+            } else {
+                $_groups = $test->groups();
             }
 
-            foreach ($test->groups() as $group) {
+            foreach ($_groups as $group) {
                 if (!isset($groups[$group])) {
                     $groups[$group] = 1;
                 } else {