Issue #3222069 by larowlan: Add test coverage

tests/src/Functional/LinkIframeFormatterTest.php

+<?php
+
+namespace Drupal\Tests\link_iframe_formatter\Functional;
+
+use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
+use Drupal\entity_test\Entity\EntityTest;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Defines a class for testing link iframe formatter.
+ */
+class LinkIframeFormatterTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'field',
+    'link',
+    'link_iframe_formatter',
+    'entity_test',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+    if (!FieldStorageConfig::load('entity_test.link')) {
+      $storage = FieldStorageConfig::create([
+        'entity_type' => 'entity_test',
+        'field_name' => 'link',
+        'id' => 'entity_test.link',
+        'type' => 'link',
+      ]);
+      $storage->save();
+    }
+
+    if (!FieldConfig::load('entity_test.entity_test.link')) {
+      $config = FieldConfig::create([
+        'field_name' => 'link',
+        'entity_type' => 'entity_test',
+        'bundle' => 'entity_test',
+        'id' => 'entity_test.entity_test.link',
+        'label' => 'Link',
+      ]);
+      $config->save();
+    }
+    $display = \Drupal::service('entity_display.repository')->getViewDisplay('entity_test', 'entity_test');
+    assert($display instanceof EntityViewDisplayInterface);
+    $display->setComponent('link', [
+      'type' => 'link_iframe_formatter',
+      'settings' => [
+        'width' => 350,
+        'height' => 270,
+        'class' => 'some-class',
+        'original' => TRUE,
+      ],
+    ]);
+    $display->save();
+  }
+
+  /**
+   * Tests formatter.
+   */
+  public function testFormatter(): void {
+    $this->drupalLogin($this->createUser(['access content', 'view test entity']));
+    $url = sprintf('https://%s.com/index.html', $this->randomMachineName());
+    $entity = EntityTest::create([
+      'name' => $this->randomMachineName(),
+      'type' => 'entity_test',
+      'link' => [
+        'uri' => $url,
+      ],
+    ]);
+    $entity->save();
+    $this->drupalGet($entity->toUrl());
+    $iframe = $this->assertSession()->elementExists('css', sprintf('iframe[src="%s"]', $url));
+    $this->assertEquals(270, $iframe->getAttribute('height'));
+    $this->assertEquals(350, $iframe->getAttribute('width'));
+    $this->assertEquals('some-class', $iframe->getAttribute('class'));
+    $link = $this->assertSession()->elementExists('named', ['link', $url]);
+    $this->assertEquals($url, $link->getAttribute('href'));
+    $this->assertSession()->pageTextContains('You may view the original link at');
+  }
+
+}