Issue #3114041 by swatichouhan012, longwave, chr.fritsch, alexpott, mondrake:...

Issue #3114041 by swatichouhan012, longwave, chr.fritsch, alexpott, mondrake: PhpUnit 8 tests breaking because of compatibility issue with setUp()

core/tests/Drupal/TestTools/PhpUnitCompatibility/PhpUnit8/ClassWriter.php

@@ -43,9 +43,14 @@ public static function mutateTestBase($autoloader) {
     $alteredCode = file_get_contents($alteredFile = $vendor_dir . '/phpunit/phpunit/src/Framework/TestCase.php');
     $alteredCode = preg_replace('/^    ((?:protected|public)(?: static)? function \w+\(\)): void/m', '    $1', $alteredCode);
     $alteredCode = str_replace("__DIR__ . '/../Util/", "'$vendor_dir/phpunit/phpunit/src/Util/", $alteredCode);
-    $filename = __DIR__ . '/../../../../../../sites/simpletest/TestCase.php';
+    $simpletest_directory = __DIR__ . '/../../../../../../sites/simpletest';
     // Only write when necessary.
+    $filename = $simpletest_directory . '/TestCase.php';
     if (!file_exists($filename) || md5_file($filename) !== md5($alteredCode)) {
+      // Create directory when necessary.
+      if (!file_exists($simpletest_directory)) {
+        mkdir($simpletest_directory, 0777, TRUE);
+      }
       file_put_contents($filename, $alteredCode);
     }
     include $filename;