Add test and reduce comment lenght

modules/config_simple_example/config_simple_example.module

@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Demonstrates how to create a custom config, config form and config translation.
+ * Demonstrates how to create a translatable custom configuration form.
  */
 
 /**

modules/config_simple_example/tests/src/Functional/ConfigExampleTest.php

+<?php
+
+namespace Drupal\Tests\form_api_example\Functional;
+
+use Drupal\Core\Url;
+use Drupal\language\Entity\ConfigurableLanguage;
+use Drupal\Tests\examples\Functional\ExamplesBrowserTestBase;
+
+/**
+ * Ensure that the form_api_example forms work properly.
+ *
+ * @group config_simple_example
+ * @group examples
+ *
+ * @ingroup form_api_example
+ */
+class ConfigExampleTest extends ExamplesBrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Our module dependencies.
+   *
+   * @var string[]
+   */
+  protected static $modules = [
+    'language',
+    'locale',
+    'config_simple_example',
+  ];
+
+  /**
+   * The installation profile to use with this test.
+   *
+   * @var string
+   */
+  protected $profile = 'minimal';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+    // We need more language than default English.
+    $language = ConfigurableLanguage::createFromLangcode('es');
+    $language->save();
+  }
+
+  /**
+   * Aggregate all the tests.
+   *
+   * Since this is a functional test, and we don't expect to need isolation
+   * between these form tests, we'll aggregate them here for speed's sake. That
+   * way the testing system doesn't have to rebuild a new Drupal for us for each
+   * test.
+   */
+  public function testFunctional() {
+    // Please fail this one first.
+    $this->doTestMainPage();
+    $this->doTestConfigSimpleForm();
+  }
+
+  /**
+   * Test the main page.
+   */
+  public function doTestMainPage() {
+    $assert = $this->assertSession();
+    $example_page = Url::fromRoute('config_simple_example.description');
+    $this->drupalGet($example_page);
+
+    $assert->pageTextContains('The Config Simple Example module defines a simple translatable config form.');
+    $assert->linkExists('Config Simple Form');
+  }
+
+  /**
+   * Test the config simple form.
+   */
+  public function doTestConfigSimpleForm() {
+    $assert = $this->assertSession();
+    $config_page = Url::fromRoute('config_simple_example.settings');
+    $this->drupalGet($config_page);
+
+    $assert->fieldEnabled('edit-message');
+    $assert->buttonExists('edit-submit');
+
+    // Ensure the 'Save configuration' action performs the save.
+    $this->drupalGet($config_page);
+    $edit = [
+      'message' => 'Message in EN',
+    ];
+    $this->submitForm($edit, 'Save configuration');
+    $assert->pageTextContains('Message in EN');
+
+    // Go to Spanish version.
+    $es_lang_object = \Drupal::languageManager()->getLanguage('es');
+    $config_page_es = Url::fromRoute('config_simple_example.settings', [], ['language' => $es_lang_object]);
+    $this->drupalGet($config_page_es);
+
+    $assert->fieldEnabled('edit-message');
+    $assert->buttonExists('edit-submit');
+
+    // Ensure the 'Save configuration' action performs the save.
+    $this->drupalGet($config_page);
+    $edit = [
+      'message' => 'Message in ES',
+    ];
+    $this->submitForm($edit, 'Save configuration');
+    $assert->pageTextContains('Message in ES');
+
+    // Go back to original English version.
+    $this->drupalGet($config_page);
+    $assert->pageTextContains('Message in EN');
+  }
+
+}