Issue #2809529 by Lendude, martin107: Convert AJAX part of \Drupal\system\Tests\Ajax\ElementValidationTest::testAjaxElementValidation to JavascriptTestBase

(cherry picked from commit ebee0dc)

Author: larowlan

core/modules/system/src/Tests/Ajax/ElementValidationTest.php

@@ -0,0 +1,53 @@
+<?php
+
+namespace Drupal\FunctionalJavascriptTests\Ajax;
+
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
+
+/**
+ * Various tests of AJAX behavior.
+ *
+ * @group Ajax
+ */
+class ElementValidationTest extends WebDriverTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['ajax_test', 'ajax_forms_test'];
+
+  /**
+   * Tries to post an Ajax change to a form that has a validated element.
+   *
+   * Drupal AJAX commands update the DOM echoing back the validated values in
+   * the form of messages that appear on the page.
+   */
+  public function testAjaxElementValidation() {
+    $this->drupalGet('ajax_validation_test');
+    $page = $this->getSession()->getPage();
+    $assert = $this->assertSession();
+
+    // Partially complete the form with a string.
+    $page->fillField('drivertext', 'some dumb text');
+    // Move focus away from this field to trigger AJAX.
+    $page->findField('spare_required_field')->focus();
+
+    // When the AJAX command updates the DOM a <ul> unsorted list
+    // "message__list" structure will appear on the page echoing back the
+    // "some dumb text" message.
+    $placeholder_text = $assert->waitForElement('css', "ul.messages__list li.messages__item em:contains('some dumb text')");
+    $this->assertNotNull($placeholder_text, 'A callback successfully echoed back a string.');
+
+    $this->drupalGet('ajax_validation_test');
+    // Partialy complete the form with a number.
+    $page->fillField('drivernumber', '12345');
+    $page->findField('spare_required_field')->focus();
+
+    // The AJAX request/resonse will complete successfully when a InsertCommand
+    // injects a message with a placeholder element into the DOM with the
+    // submitted number.
+    $placeholder_number = $assert->waitForElement('css', "ul.messages__list li.messages__item em:contains('12345')");
+    $this->assertNotNull($placeholder_number, 'A callback successfully echoed back a number.');
+  }
+
+}