diff --git a/core/tests/Drupal/FunctionalTests/SetupDrupalTestScript.php b/core/tests/Drupal/FunctionalTests/SetupDrupalTestScript.php
new file mode 100644
index 0000000000..badf721745
--- /dev/null
+++ b/core/tests/Drupal/FunctionalTests/SetupDrupalTestScript.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Drupal\FunctionalTests;
+
+use Drupal\Setup\TestSetupInterface;
+
+/**
+ * Tests setup-drupal-test.php.
+ *
+ * @group core
+ */
+class SetupDrupalTestScript implements TestSetupInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setup() {
+    \Drupal::service('module_installer')->install(['test_page_test']);
+  }
+
+}
diff --git a/core/tests/Drupal/FunctionalTests/SetupDrupalTestScriptTest.php b/core/tests/Drupal/FunctionalTests/SetupDrupalTestScriptTest.php
index 3a0487092c..4c5adf5a4e 100644
--- a/core/tests/Drupal/FunctionalTests/SetupDrupalTestScriptTest.php
+++ b/core/tests/Drupal/FunctionalTests/SetupDrupalTestScriptTest.php
@@ -2,28 +2,29 @@
 
 namespace Drupal\FunctionalTests;
 
-use Drupal\Tests\UnitTestCase;
-use Symfony\Component\Process\PhpExecutableFinder;
-use Symfony\Component\Process\Process;
+use Drupal\Setup\Commands\TestInstallationSetupApplication;
+use Drupal\Tests\BrowserTestBase;
+use Symfony\Component\Console\Tester\ApplicationTester;
 
 /**
  * Tests setup-drupal-test.php.
  *
  * @group core
  */
-class SetupDrupalTestScriptTest extends UnitTestCase {
+class SetupDrupalTestScriptTest extends BrowserTestBase {
 
   public function testInstallScript() {
-    $php_executable_finder = new PhpExecutableFinder();
-    $php = $php_executable_finder->find();
+    $app = new TestInstallationSetupApplication();
 
-    $db_url = getenv('SIMPLETEST_DB');
-    $base_url = getenv('SIMPLETEST_BASE_URL');
-    $process = new Process("$php {$this->root}/core/scripts/setup-drupal-test.php --db_url={$db_url} --base_url={$base_url}");
-    $process->run(function ($type, $data) {
-      // @todo How does one test an async API?
-      // This code might happen after the test function is done.
-    });
+    $options = [
+      'setup_file' => __DIR__ . '/SetupDrupalTestScript.php',
+    ];
+    $app_tester = new ApplicationTester($app);
+    $output = $app_tester->run([
+      'command' => 'run',
+    ], $options);
+    $a = 123;
+    $this->assertTrue(FALSE);
   }
 
 }
diff --git a/core/tests/Drupal/Setup/TestInstallationSetup.php b/core/tests/Drupal/Setup/TestInstallationSetup.php
index c0bde3851f..714b2815e4 100644
--- a/core/tests/Drupal/Setup/TestInstallationSetup.php
+++ b/core/tests/Drupal/Setup/TestInstallationSetup.php
@@ -99,12 +99,13 @@ protected function executeSetupFile($setup_file) {
     if (count($classes) > 1) {
       throw new \InvalidArgumentException(sprintf('You need to define a single class implementing \Drupal\Setup\TestSetupInterface'));
     }
+
+    require_once $setup_file;
+
     if (!is_subclass_of($classes[0], TestSetupInterface::class)) {
       throw new \InvalidArgumentException(sprintf('You need to define a class implementing \Drupal\Setup\TestSetupInterface'));
     }
 
-    require_once $setup_file;
-
     /** @var \Drupal\Setup\TestSetupInterface $instance */
     $instance = new $classes[0];
     $instance->setup();