Add drupal_messages Twig function.

src/TwigExtension.php

@@ -45,6 +45,7 @@ class TwigExtension extends \Twig_Extension {
       new \Twig_SimpleFunction('drupal_title', [$this, 'drupalTitle']),
       new \Twig_SimpleFunction('drupal_url', [$this, 'drupalUrl']),
       new \Twig_SimpleFunction('drupal_link', [$this, 'drupalLink']),
+      new \Twig_SimpleFunction('drupal_messages', [$this, 'drupalMessages']),
     ];
   }
 
@@ -507,6 +508,13 @@ class TwigExtension extends \Twig_Extension {
     }
   }
 
+  /**
+   * Displays status messages.
+   */
+  public function drupalMessages() {
+    return ['#type' => 'status_messages'];
+  }
+
   /**
    * Replaces all tokens in a given string with appropriate values.
    *

tests/src/Functional/TwigTweakTest.php

@@ -195,6 +195,10 @@ class TwigTweakTest extends BrowserTestBase {
     $xpath = '//div[@class = "tt-link"]';
     self::assertEquals($link, trim($this->xpath($xpath)[0]->getHtml()));
 
+    // Test status messages.
+    $xpath = '//div[@class = "tt-messages"]/div[contains(@class, "messages--status") and contains(., "Hello world!")]';
+    $this->assertByXpath($xpath);
+
     // Test protected link.
     $xpath = '//div[@class = "tt-link-access"]';
     self::assertEquals('', trim($this->xpath($xpath)[0]->getHtml()));

tests/twig_tweak_test/templates/twig-tweak-test.html.twig

@@ -43,6 +43,7 @@
   <div class="tt-title">{{ drupal_title() }}</div>
   <div class="tt-url">{{ drupal_url('node/1', {absolute: true}) }}</div>
   <div class="tt-link">{{ drupal_link('Edit', 'node/1/edit', {absolute: true}) }}</div>
+  <div class="tt-messages">{{ drupal_messages() }}</div>
   <div class="tt-link-access">{{ drupal_link('Edit', 'node/1/edit', {absolute: true}, true) }}</div>
   <div class="tt-token-replace">{{ 'Site name: [site:name]' | token_replace }}</div>
   <div class="tt-preg-replace">{{ 'FOO' | preg_replace('/(foo)/i', '$1-bar') }}</div>

tests/twig_tweak_test/twig_tweak_test.info.yml

@@ -1,8 +1,9 @@
 name: Twig tweak test
 type: module
-description: Support module for Tweak twig testing.
+description: Support module for Twig tweak testing.
 package: Testing
 core: 8.x
 dependencies:
+  - drupal:system (>= 8.5.0)
   - drupal:node
   - drupal:twig_tweak

tests/twig_tweak_test/twig_tweak_test.module

@@ -9,6 +9,7 @@
  * Implements hook_page_bottom().
  */
 function twig_tweak_test_page_bottom(array &$page_bottom) {
+  \Drupal::service('messenger')->addMessage('Hello world!');
   $page_bottom['twig_tweak_test']['#theme'] = 'twig_tweak_test';
 }