Issue #3401146: Added basic drupalSettings merging test.

modules/refreshless_turbo/tests/src/FunctionalJavascript/DrupalSettingsTest.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\refreshless_turbo\FunctionalJavascript;
+
+use Drupal\Core\Url;
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
+use Drupal\Tests\refreshless_turbo\FunctionalJavascript\TurboAssertTrait;
+use Drupal\Tests\refreshless_turbo\FunctionalJavascript\TurboHtmlDebugTrait;
+
+/**
+ * drupalSettings updater tests.
+ *
+ * @group refreshless
+ *
+ * @group refreshless_turbo
+ */
+class DrupalSettingsTest extends WebDriverTestBase {
+
+  use TurboAssertTrait;
+
+  use TurboHtmlDebugTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['block', 'refreshless_turbo', 'system'];
+
+  /**
+   * Assert that a drupalSettings property equals an expected value.
+   *
+   * @param string $propertyName
+   *   The property name. Note that 'drupalSettings.' is prepended automatically
+   *   and so should not be included.
+   *
+   * @param string $expectedValue
+   *   The expected value of the property.
+   */
+  protected function assertDrupalSettingsValue(
+    string $propertyName, string $expectedValue,
+  ): void {
+
+    $actualValue = $this->getSession()->evaluateScript(<<<JS
+      return drupalSettings.{$propertyName};
+    JS);
+
+    $this->assertEquals(
+      $expectedValue, $actualValue,
+      "drupalSettings.$propertyName was expected to equal \"$expectedValue\" but got \"$actualValue\"!",
+    );
+
+  }
+
+  /**
+   * Test that drupalSettings updates are merged when navigating to new pages.
+   */
+  public function testMerging(): void {
+
+    $this->drupalPlaceBlock('local_tasks_block', [
+      'region' => 'content', 'id' => 'local-tasks-block',
+    ]);
+
+    $loginUrl = Url::fromRoute('user.login');
+
+    $registerUrl = Url::fromRoute('user.register');
+
+    $resetPasswordUrl = Url::fromRoute('user.pass');
+
+    $this->drupalGet($loginUrl);
+
+    $this->assertSession()->assertTurboIsPresent();
+
+    $this->assertSession()->startTurboPersist();
+
+    $this->assertDrupalSettingsValue(
+      'path.currentPath', $loginUrl->getInternalPath(),
+    );
+
+    $this->click('[data-drupal-link-system-path="' .
+      $registerUrl->getInternalPath() .
+    '"]');
+
+    $this->assertSession()->assertWaitOnTurboRequest();
+
+    $this->assertSession()->assertTurboPersisted();
+
+    $this->assertDrupalSettingsValue(
+      'path.currentPath', $registerUrl->getInternalPath(),
+    );
+
+    $this->turboHtmlOutput();
+
+    $this->click('[data-drupal-link-system-path="' .
+      $resetPasswordUrl->getInternalPath() .
+    '"]');
+
+    $this->assertSession()->assertWaitOnTurboRequest();
+
+    $this->assertSession()->assertTurboPersisted();
+
+    $this->assertDrupalSettingsValue(
+      'path.currentPath', $resetPasswordUrl->getInternalPath(),
+    );
+
+    $this->turboHtmlOutput();
+
+  }
+
+}