--- /dev/null
+<?php
+
+namespace Drupal\Tests\comment\Kernel\Migrate\d6;
+
+use Drupal\Core\Entity\Entity\EntityFormDisplay;
+use Drupal\Tests\migrate_drupal\Kernel\d6\MigrateDrupal6TestBase;
+
+/**
+ * Tests the migration of comment form's subject display from Drupal 6.
+ *
+ * @group comment
+ * @group migrate_drupal_6
+ */
+class MigrateCommentEntityFormDisplaySubjectTest extends MigrateDrupal6TestBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public static $modules = ['comment'];
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function setUp() {
+ parent::setUp();
+ $this->installConfig(['comment']);
+ $this->executeMigrations([
+ 'd6_comment_type',
+ 'd6_comment_entity_form_display_subject',
+ ]);
+ }
+
+ /**
+ * Asserts that the comment subject field is visible for a node type.
+ *
+ * @param string $id
+ * The entity form display ID.
+ */
+ protected function assertSubjectVisible($id) {
+ $component = EntityFormDisplay::load($id)->getComponent('subject');
+ $this->assertInternalType('array', $component);
+ $this->assertSame('string_textfield', $component['type']);
+ $this->assertSame(10, $component['weight']);
+ }
+
+ /**
+ * Asserts that the comment subject field is not visible for a node type.
+ *
+ * @param string $id
+ * The entity form display ID.
+ */
+ protected function assertSubjectNotVisible($id) {
+ $component = EntityFormDisplay::load($id)->getComponent('subject');
+ $this->assertNull($component);
+ }
+
+ /**
+ * Tests the migrated display configuration.
+ */
+ public function testMigration() {
+ $this->assertSubjectVisible('comment.comment_node_article.default');
+ $this->assertSubjectVisible('comment.comment_node_company.default');
+ $this->assertSubjectVisible('comment.comment_node_employee.default');
+ $this->assertSubjectVisible('comment.comment_node_page.default');
+ $this->assertSubjectVisible('comment.comment_node_sponsor.default');
+ $this->assertSubjectNotVisible('comment.comment_node_story.default');
+ $this->assertSubjectVisible('comment.comment_node_test_event.default');
+ $this->assertSubjectVisible('comment.comment_node_test_page.default');
+ $this->assertSubjectVisible('comment.comment_node_test_planet.default');
+ $this->assertSubjectVisible('comment.comment_node_test_story.default');
+ }
+
+}