--- /dev/null
+<?php
+
+namespace Drupal\Tests\toolbar\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Tests the implementation of hook_toolbar() by a module.
+ *
+ * @group toolbar
+ */
+class ToolbarHookToolbarTest extends BrowserTestBase {
+
+ /**
+ * A user with permission to access the administrative toolbar.
+ *
+ * @var \Drupal\user\UserInterface
+ */
+ protected $adminUser;
+
+ /**
+ * Modules to enable.
+ *
+ * @var array
+ */
+ public static $modules = ['toolbar', 'toolbar_test', 'test_page_test'];
+
+ protected function setUp() {
+ parent::setUp();
+
+ // Create an administrative user and log it in.
+ $this->adminUser = $this->drupalCreateUser(['access toolbar']);
+ $this->drupalLogin($this->adminUser);
+ }
+
+ /**
+ * Tests for a tab and tray provided by a module implementing hook_toolbar().
+ */
+ public function testHookToolbar() {
+ $this->drupalGet('test-page');
+ $this->assertResponse(200);
+
+ // Assert that the toolbar is present in the HTML.
+ $this->assertRaw('id="toolbar-administration"');
+
+ // Assert that the tab registered by toolbar_test is present.
+ $this->assertRaw('id="toolbar-tab-testing"');
+
+ // Assert that the tab item descriptions are present.
+ $this->assertRaw('title="Test tab"');
+
+ // Assert that the tray registered by toolbar_test is present.
+ $this->assertRaw('id="toolbar-tray-testing"');
+
+ // Assert that tray item descriptions are present.
+ $this->assertRaw('title="Test link 1 title"');
+ }
+
+}