Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

core/modules/simpletest/tests/fixtures/simpletest_phpunit_run_command_test.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace Drupal\Tests\simpletest\Unit;
+
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * This test crashes PHP.
+ *
+ * To avoid accidentally running, it is not in a normal PSR-4 directory, the
+ * file name does not adhere to PSR-4 and an environment variable also needs to
+ * be set for the crash to happen.
+ */
+class SimpletestPhpunitRunCommandTestWillDie extends UnitTestCase {
+
+  public function testWillDie() {
+    if (getenv('SimpletestPhpunitRunCommandTestWillDie') === 'fail') {
+      exit(1);
+    }
+  }
+}
+