core/scripts/test-site.php                         |  2 +-
 .../TestSite/Commands/TestSiteInstallCommand.php   |  2 +-
 .../TestSite/Commands/TestSiteTearDownCommand.php  |  4 +--
 core/tests/Drupal/TestSite/TestSetupInterface.php  |  2 +-
 .../Tests/Scripts/TestSiteApplicationTest.php      | 33 +++++++++++++++-------
 5 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/core/scripts/test-site.php b/core/scripts/test-site.php
index d3fb826..3e33fab 100644
--- a/core/scripts/test-site.php
+++ b/core/scripts/test-site.php
@@ -3,7 +3,7 @@
 
 /**
  * @file
- * A command line application to install drupal for tests.
+ * A command line application to install Drupal for tests.
  */
 
 use Drupal\TestSite\TestSiteApplication;
diff --git a/core/tests/Drupal/TestSite/Commands/TestSiteInstallCommand.php b/core/tests/Drupal/TestSite/Commands/TestSiteInstallCommand.php
index e61d264..6f122d8 100644
--- a/core/tests/Drupal/TestSite/Commands/TestSiteInstallCommand.php
+++ b/core/tests/Drupal/TestSite/Commands/TestSiteInstallCommand.php
@@ -188,7 +188,7 @@ protected function installDrupal() {
    * Uses the setup file to configure Drupal.
    *
    * @param string $class
-   *   The full qualified class name, which should setup Drupal for tests. For
+   *   The fully qualified class name, which should set up Drupal for tests. For
    *   example this class could create content types and fields or install
    *   modules. The class needs to implement TestSetupInterface.
    *
diff --git a/core/tests/Drupal/TestSite/Commands/TestSiteTearDownCommand.php b/core/tests/Drupal/TestSite/Commands/TestSiteTearDownCommand.php
index 6dce953..e2f355b 100644
--- a/core/tests/Drupal/TestSite/Commands/TestSiteTearDownCommand.php
+++ b/core/tests/Drupal/TestSite/Commands/TestSiteTearDownCommand.php
@@ -92,12 +92,12 @@ protected function tearDown(TestDatabase $test_database, $db_url) {
   }
 
   /**
-   * Deletes all files and directories in the specified filepath recursively.
+   * Deletes all files and directories in the specified path recursively.
    *
    * Note this version has no dependencies on Drupal core to ensure that the
    * test site can be torn down even if something in the test site is broken.
    *
-   * @param $path
+   * @param string $path
    *   A string containing either an URI or a file or directory path.
    * @param callable $callback
    *   (optional) Callback function to run on each file prior to deleting it and
diff --git a/core/tests/Drupal/TestSite/TestSetupInterface.php b/core/tests/Drupal/TestSite/TestSetupInterface.php
index 985f267..06c9717 100644
--- a/core/tests/Drupal/TestSite/TestSetupInterface.php
+++ b/core/tests/Drupal/TestSite/TestSetupInterface.php
@@ -3,7 +3,7 @@
 namespace Drupal\TestSite;
 
 /**
- * Allows you to setup an environment as part of a test site install.
+ * Allows setting up an environment as part of a test site install.
  *
  * @see \Drupal\TestSite\Commands\TestSiteInstallCommand
  */
diff --git a/core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php b/core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php
index 9136f61..4c2444e 100644
--- a/core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php
+++ b/core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php
@@ -18,7 +18,7 @@
  * @group Setup
  *
  * This test uses the Drupal\Core\Database\Database class which has a static.
- * Therefore run in an separate process to avoid side effects.
+ * Therefore run in a separate process to avoid side effects.
  *
  * @runTestsInSeparateProcesses
  * @preserveGlobalState disabled
@@ -108,8 +108,8 @@ public function testInstallScript() {
     // Ensure the test_page_test module got installed.
     $this->assertContains('Test page | Drupal', (string) $response->getBody());
 
-    // Ensure that there are files and database tables for tear down command to
-    // clean up.
+    // Ensure that there are files and database tables for the tear down command
+    // to clean up.
     $key = $this->addTestDatabase($db_prefix);
     $this->assertGreaterThan(0, count(Database::getConnection('default', $key)->schema()->findTables('%')));
     $test_database = new TestDatabase($db_prefix);
@@ -119,8 +119,8 @@ public function testInstallScript() {
     // Ensure the lock file exists.
     $this->assertFileExists($this->getTestLockFile($db_prefix));
 
-    // Install another site so we can ensure tear down only removes one site at
-    // a time. Use the regular output.
+    // Install another site so we can ensure the tear down command only removes
+    // one site at a time. Use the regular output.
     $command_line = $php_binary_path . ' core/scripts/test-site.php install --setup_class "' . TestSiteInstallTestScript::class . '" --db_url "' . getenv('SIMPLETEST_DB') . '"';
     $process = new Process($command_line, $this->root);
     // Set the timeout to a value that allows debugging.
@@ -138,7 +138,7 @@ public function testInstallScript() {
     // Ensure the lock file exists for the new install.
     $this->assertFileExists($this->getTestLockFile($other_db_prefix));
 
-    // Now test the tear down process as well.
+    // Now test the tear down process as well, but keep the lock.
     $command_line = $php_binary_path . ' core/scripts/test-site.php tear-down ' . $db_prefix . ' --keep_lock --db_url "' . getenv('SIMPLETEST_DB') . '"';
     $process = new Process($command_line, $this->root);
     // Set the timeout to a value that allows debugging.
@@ -157,8 +157,8 @@ public function testInstallScript() {
     $test_file = $this->root . DIRECTORY_SEPARATOR . $test_database->getTestSitePath() . DIRECTORY_SEPARATOR . '.htkey';
     $this->assertFileExists($test_file);
 
-    // Tear down the other site installed. Tear down should work if the test
-    // site is broken. Prove this by removing its settings.php.
+    // Tear down the other site. Tear down should work if the test site is
+    // broken. Prove this by removing its settings.php.
     $test_site_settings = $this->root . DIRECTORY_SEPARATOR . $test_database->getTestSitePath() . DIRECTORY_SEPARATOR . 'settings.php';
     $this->assertTrue(unlink($test_site_settings));
     $command_line = $php_binary_path . ' core/scripts/test-site.php tear-down ' . $other_db_prefix . ' --db_url "' . getenv('SIMPLETEST_DB') . '"';
@@ -173,10 +173,23 @@ public function testInstallScript() {
     $this->assertCount(0, Database::getConnection('default', $other_key)->schema()->findTables('%'));
     $this->assertFileNotExists($test_file);
 
-    // The lock for the first site should still exist but the second site is
-    // clean up during tear down.
+    // The lock for the first site should still exist but the second site's lock
+    // is released during tear down.
     $this->assertFileExists($this->getTestLockFile($db_prefix));
     $this->assertFileNotExists($this->getTestLockFile($other_db_prefix));
+
+    // Release all locks.
+    $command_line = $php_binary_path . ' core/scripts/test-site.php release-locks';
+    $process = new Process($command_line, $this->root);
+    // Set the timeout to a value that allows debugging.
+    $process->setTimeout(500);
+    $process->run();
+    $this->assertSame(0, $process->getExitCode());
+    $this->assertContains("Successfully released all the test database locks", $process->getOutput());
+
+    // Both tests sites' locks should no longer exist now.
+    $this->assertFileNotExists($this->getTestLockFile($db_prefix));
+    $this->assertFileNotExists($this->getTestLockFile($other_db_prefix));
   }
 
   /**