diff --git a/core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php b/core/tests/Drupal/Tests/Core/Scripts/TestSiteApplicationTest.php
similarity index 97%
rename from core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php
rename to core/tests/Drupal/Tests/Core/Scripts/TestSiteApplicationTest.php
index c8d5b81173..7b6d08ea2a 100644
--- a/core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php
+++ b/core/tests/Drupal/Tests/Core/Scripts/TestSiteApplicationTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\Tests\Scripts;
+namespace Drupal\Tests\Core\Scripts;
 
 use Drupal\Component\FileSystem\FileSystem;
 use Drupal\Core\Database\Database;
@@ -25,6 +25,9 @@
  * @see \Drupal\TestSite\TestSiteApplication
  * @see \Drupal\TestSite\Commands\TestSiteInstallCommand
  * @see \Drupal\TestSite\Commands\TestSiteTearDownCommand
+ *
+ * @todo Move this into a separate Scripts namespace after
+ *   https://www.drupal.org/project/drupal/issues/2878269
  */
 class TestSiteApplicationTest extends UnitTestCase {
 
@@ -34,7 +37,7 @@ class TestSiteApplicationTest extends UnitTestCase {
   protected function setUp() {
     parent::setUp();
     $this->root = dirname(dirname(substr(__DIR__, 0, -strlen(__NAMESPACE__))));
-    }
+  }
 
   /**
    * Gets the connection object for the specified database key and target.
@@ -113,7 +116,7 @@ public function testInstallWithNonSetupClass() {
     $process = new Process($command_line, $this->root, ['COLUMNS' => PHP_INT_MAX]);
     $process->run();
 
-    $this->assertContains('The class Drupal\Tests\Scripts\TestSiteApplicationTest contained in', $process->getErrorOutput());
+    $this->assertContains('The class Drupal\Tests\Core\Scripts\TestSiteApplicationTest contained in', $process->getErrorOutput());
     $this->assertContains('needs to implement \Drupal\TestSite\TestSetupInterface', $process->getErrorOutput());
     $this->assertSame(1, $process->getExitCode());
     $this->assertCount($table_count, $connection->schema()->findTables('%'), 'No additional tables created in the database');
@@ -295,7 +298,8 @@ public function testTearDownDbPrefixValidation() {
    *   The database key of the added connection.
    */
   protected function addTestDatabase($db_prefix) {
-    if (getenv('SIMPLETEST_DB') === FALSE) {
+    // If SIMPLETEST_DB is not set, it will be FALSE. It could also be empty.
+    if (empty(getenv('SIMPLETEST_DB'))) {
       $this->markTestSkipped('Needs the SIMPLETEST_DB environmental variable in order to install to a database.');
     }
     $database = Database::convertDbUrlToConnectionInfo(getenv('SIMPLETEST_DB'), $this->root);