diff --git a/core/modules/migrate_drupal/migration_templates/d6_comment.yml b/core/modules/comment/migration_templates/d6_comment.yml
similarity index 100%
rename from core/modules/migrate_drupal/migration_templates/d6_comment.yml
rename to core/modules/comment/migration_templates/d6_comment.yml
diff --git a/core/modules/migrate_drupal/migration_templates/d6_comment_entity_display.yml b/core/modules/comment/migration_templates/d6_comment_entity_display.yml
similarity index 100%
rename from core/modules/migrate_drupal/migration_templates/d6_comment_entity_display.yml
rename to core/modules/comment/migration_templates/d6_comment_entity_display.yml
diff --git a/core/modules/migrate_drupal/migration_templates/d6_comment_entity_form_display.yml b/core/modules/comment/migration_templates/d6_comment_entity_form_display.yml
similarity index 100%
rename from core/modules/migrate_drupal/migration_templates/d6_comment_entity_form_display.yml
rename to core/modules/comment/migration_templates/d6_comment_entity_form_display.yml
diff --git a/core/modules/migrate_drupal/migration_templates/d6_comment_entity_form_display_subject.yml b/core/modules/comment/migration_templates/d6_comment_entity_form_display_subject.yml
similarity index 100%
rename from core/modules/migrate_drupal/migration_templates/d6_comment_entity_form_display_subject.yml
rename to core/modules/comment/migration_templates/d6_comment_entity_form_display_subject.yml
diff --git a/core/modules/migrate_drupal/migration_templates/d6_comment_field.yml b/core/modules/comment/migration_templates/d6_comment_field.yml
similarity index 100%
rename from core/modules/migrate_drupal/migration_templates/d6_comment_field.yml
rename to core/modules/comment/migration_templates/d6_comment_field.yml
diff --git a/core/modules/migrate_drupal/migration_templates/d6_comment_field_instance.yml b/core/modules/comment/migration_templates/d6_comment_field_instance.yml
similarity index 100%
rename from core/modules/migrate_drupal/migration_templates/d6_comment_field_instance.yml
rename to core/modules/comment/migration_templates/d6_comment_field_instance.yml
diff --git a/core/modules/migrate_drupal/migration_templates/d6_comment_type.yml b/core/modules/comment/migration_templates/d6_comment_type.yml
similarity index 100%
rename from core/modules/migrate_drupal/migration_templates/d6_comment_type.yml
rename to core/modules/comment/migration_templates/d6_comment_type.yml
diff --git a/core/modules/migrate_drupal/src/Plugin/migrate/source/d6/Comment.php b/core/modules/comment/src/Plugin/migrate/source/d6/Comment.php
similarity index 96%
rename from core/modules/migrate_drupal/src/Plugin/migrate/source/d6/Comment.php
rename to core/modules/comment/src/Plugin/migrate/source/d6/Comment.php
index 56575a9..08a1013 100644
--- a/core/modules/migrate_drupal/src/Plugin/migrate/source/d6/Comment.php
+++ b/core/modules/comment/src/Plugin/migrate/source/d6/Comment.php
@@ -2,10 +2,10 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Plugin\migrate\source\d6\Comment.
+ * Contains \Drupal\comment\Plugin\migrate\source\d6\Comment.
  */
 
-namespace Drupal\migrate_drupal\Plugin\migrate\source\d6;
+namespace Drupal\comment\Plugin\migrate\source\d6;
 
 use Drupal\migrate\Row;
 use Drupal\migrate_drupal\Plugin\migrate\source\DrupalSqlBase;
diff --git a/core/modules/migrate_drupal/src/Plugin/migrate/source/d6/CommentVariable.php b/core/modules/comment/src/Plugin/migrate/source/d6/CommentVariable.php
similarity index 95%
rename from core/modules/migrate_drupal/src/Plugin/migrate/source/d6/CommentVariable.php
rename to core/modules/comment/src/Plugin/migrate/source/d6/CommentVariable.php
index 8dfb5a8..96444e1 100644
--- a/core/modules/migrate_drupal/src/Plugin/migrate/source/d6/CommentVariable.php
+++ b/core/modules/comment/src/Plugin/migrate/source/d6/CommentVariable.php
@@ -2,10 +2,10 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Plugin\migrate\source\d6\CommentVariable.
+ * Contains \Drupal\comment\Plugin\migrate\source\d6\CommentVariable.
  */
 
-namespace Drupal\migrate_drupal\Plugin\migrate\source\d6;
+namespace Drupal\comment\Plugin\migrate\source\d6;
 
 use Drupal\migrate_drupal\Plugin\migrate\source\DrupalSqlBase;
 
diff --git a/core/modules/migrate_drupal/src/Plugin/migrate/source/d6/CommentVariablePerCommentType.php b/core/modules/comment/src/Plugin/migrate/source/d6/CommentVariablePerCommentType.php
similarity index 92%
rename from core/modules/migrate_drupal/src/Plugin/migrate/source/d6/CommentVariablePerCommentType.php
rename to core/modules/comment/src/Plugin/migrate/source/d6/CommentVariablePerCommentType.php
index 56313fe..149b1ba 100644
--- a/core/modules/migrate_drupal/src/Plugin/migrate/source/d6/CommentVariablePerCommentType.php
+++ b/core/modules/comment/src/Plugin/migrate/source/d6/CommentVariablePerCommentType.php
@@ -2,10 +2,10 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Plugin\migrate\source\d6\CommentVariablePerCommentType.
+ * Contains \Drupal\comment\Plugin\migrate\source\d6\CommentVariablePerCommentType.
  */
 
-namespace Drupal\migrate_drupal\Plugin\migrate\source\d6;
+namespace Drupal\comment\Plugin\migrate\source\d6;
 
 /**
  * @MigrateSource(
diff --git a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentTest.php b/core/modules/comment/src/Tests/d6/MigrateCommentTest.php
similarity index 95%
rename from core/modules/migrate_drupal/src/Tests/d6/MigrateCommentTest.php
rename to core/modules/comment/src/Tests/d6/MigrateCommentTest.php
index a6efb8e..fc3cd37 100644
--- a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentTest.php
+++ b/core/modules/comment/src/Tests/d6/MigrateCommentTest.php
@@ -2,17 +2,18 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Tests\d6\MigrateCommentTest.
+ * Contains \Drupal\comment\Tests\d6\MigrateCommentTest.
  */
 
-namespace Drupal\migrate_drupal\Tests\d6;
+namespace Drupal\comment\Tests\d6;
 
 use Drupal\comment\Tests\CommentTestTrait;
+use Drupal\migrate_drupal\Tests\d6\MigrateDrupal6TestBase;
 
 /**
  * Upgrade comments.
  *
- * @group migrate_drupal
+ * @group comment
  */
 class MigrateCommentTest extends MigrateDrupal6TestBase {
 
diff --git a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentTypeTest.php b/core/modules/comment/src/Tests/d6/MigrateCommentTypeTest.php
similarity index 84%
rename from core/modules/migrate_drupal/src/Tests/d6/MigrateCommentTypeTest.php
rename to core/modules/comment/src/Tests/d6/MigrateCommentTypeTest.php
index 2b4e07d..fc94b82 100644
--- a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentTypeTest.php
+++ b/core/modules/comment/src/Tests/d6/MigrateCommentTypeTest.php
@@ -2,17 +2,18 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Tests\d6\MigrateCommentTypeTest.
+ * Contains \Drupal\comment\Tests\d6\MigrateCommentTypeTest.
  */
 
-namespace Drupal\migrate_drupal\Tests\d6;
+namespace Drupal\comment\Tests\d6;
 
 use Drupal\comment\Entity\CommentType;
+use Drupal\migrate_drupal\Tests\d6\MigrateDrupal6TestBase;
 
 /**
  * Upgrade comment type.
  *
- * @group migrate_drupal
+ * @group comment
  */
 class MigrateCommentTypeTest extends MigrateDrupal6TestBase {
 
diff --git a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableDisplayBase.php b/core/modules/comment/src/Tests/d6/MigrateCommentVariableDisplayBase.php
similarity index 90%
rename from core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableDisplayBase.php
rename to core/modules/comment/src/Tests/d6/MigrateCommentVariableDisplayBase.php
index e3a0e90..348c157 100644
--- a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableDisplayBase.php
+++ b/core/modules/comment/src/Tests/d6/MigrateCommentVariableDisplayBase.php
@@ -2,10 +2,12 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Tests\d6\MigrateCommentVariableDisplayBase.
+ * Contains \Drupal\comment\Tests\d6\MigrateCommentVariableDisplayBase.
  */
 
-namespace Drupal\migrate_drupal\Tests\d6;
+namespace Drupal\comment\Tests\d6;
+
+use Drupal\migrate_drupal\Tests\d6\MigrateDrupal6TestBase;
 
 /**
  * Base class for Drupal 6 comment variables to Drupal 8 entity display tests.
diff --git a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableEntityDisplayTest.php b/core/modules/comment/src/Tests/d6/MigrateCommentVariableEntityDisplayTest.php
similarity index 84%
rename from core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableEntityDisplayTest.php
rename to core/modules/comment/src/Tests/d6/MigrateCommentVariableEntityDisplayTest.php
index f63326b..4cbbe38 100644
--- a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableEntityDisplayTest.php
+++ b/core/modules/comment/src/Tests/d6/MigrateCommentVariableEntityDisplayTest.php
@@ -2,15 +2,15 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Tests\d6\MigrateCommentVariableEntityDisplayTest.
+ * Contains \Drupal\comment\Tests\d6\MigrateCommentVariableEntityDisplayTest.
  */
 
-namespace Drupal\migrate_drupal\Tests\d6;
+namespace Drupal\comment\Tests\d6;
 
 /**
  * Upgrade comment variables to entity.display.node.*.default.yml.
  *
- * @group migrate_drupal
+ * @group comment
  */
 class MigrateCommentVariableEntityDisplayTest extends MigrateCommentVariableDisplayBase {
 
diff --git a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableEntityFormDisplaySubjectTest.php b/core/modules/comment/src/Tests/d6/MigrateCommentVariableEntityFormDisplaySubjectTest.php
similarity index 88%
rename from core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableEntityFormDisplaySubjectTest.php
rename to core/modules/comment/src/Tests/d6/MigrateCommentVariableEntityFormDisplaySubjectTest.php
index a65c9fc..a903145 100644
--- a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableEntityFormDisplaySubjectTest.php
+++ b/core/modules/comment/src/Tests/d6/MigrateCommentVariableEntityFormDisplaySubjectTest.php
@@ -2,15 +2,17 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Tests\d6\MigrateCommentVariableEntityFormDisplaySubjectTest.
+ * Contains \Drupal\comment\Tests\d6\MigrateCommentVariableEntityFormDisplaySubjectTest.
  */
 
-namespace Drupal\migrate_drupal\Tests\d6;
+namespace Drupal\comment\Tests\d6;
+
+use Drupal\migrate_drupal\Tests\d6\MigrateDrupal6TestBase;
 
 /**
  * Upgrade comment subject variable to core.entity_form_display.comment.*.default.yml
  *
- * @group migrate_drupal
+ * @group comment
  */
 class MigrateCommentVariableEntityFormDisplaySubjectTest extends MigrateDrupal6TestBase {
 
diff --git a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableEntityFormDisplayTest.php b/core/modules/comment/src/Tests/d6/MigrateCommentVariableEntityFormDisplayTest.php
similarity index 81%
rename from core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableEntityFormDisplayTest.php
rename to core/modules/comment/src/Tests/d6/MigrateCommentVariableEntityFormDisplayTest.php
index 79d8dde..b545532 100644
--- a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableEntityFormDisplayTest.php
+++ b/core/modules/comment/src/Tests/d6/MigrateCommentVariableEntityFormDisplayTest.php
@@ -2,15 +2,15 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Tests\d6\MigrateCommentVariableEntityFormDisplayTest.
+ * Contains \Drupal\comment\Tests\d6\MigrateCommentVariableEntityFormDisplayTest.
  */
 
-namespace Drupal\migrate_drupal\Tests\d6;
+namespace Drupal\comment\Tests\d6;
 
 /**
  * Upgrade comment variables to core.entity_form_display.node.*.default.yml.
  *
- * @group migrate_drupal
+ * @group comment
  */
 class MigrateCommentVariableEntityFormDisplayTest extends MigrateCommentVariableDisplayBase {
 
diff --git a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableFieldTest.php b/core/modules/comment/src/Tests/d6/MigrateCommentVariableFieldTest.php
similarity index 87%
rename from core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableFieldTest.php
rename to core/modules/comment/src/Tests/d6/MigrateCommentVariableFieldTest.php
index c3986ba..5039198 100644
--- a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableFieldTest.php
+++ b/core/modules/comment/src/Tests/d6/MigrateCommentVariableFieldTest.php
@@ -2,17 +2,18 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Tests\d6\MigrateCommentVariableFieldTest.
+ * Contains \Drupal\comment\Tests\d6\MigrateCommentVariableFieldTest.
  */
 
-namespace Drupal\migrate_drupal\Tests\d6;
+namespace Drupal\comment\Tests\d6;
 
 use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\migrate_drupal\Tests\d6\MigrateDrupal6TestBase;
 
 /**
  * Upgrade comment variables to field.storage.node.comment.yml.
  *
- * @group migrate_drupal
+ * @group comment
  */
 class MigrateCommentVariableFieldTest extends MigrateDrupal6TestBase {
 
diff --git a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableInstanceTest.php b/core/modules/comment/src/Tests/d6/MigrateCommentVariableInstanceTest.php
similarity index 93%
rename from core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableInstanceTest.php
rename to core/modules/comment/src/Tests/d6/MigrateCommentVariableInstanceTest.php
index 22747ea..4c3a7cc 100644
--- a/core/modules/migrate_drupal/src/Tests/d6/MigrateCommentVariableInstanceTest.php
+++ b/core/modules/comment/src/Tests/d6/MigrateCommentVariableInstanceTest.php
@@ -2,15 +2,17 @@
 
 /**
  * @file
- * Contains \Drupal\migrate_drupal\Tests\d6\MigrateCommentVariableInstanceTest.
+ * Contains \Drupal\comment\Tests\d6\MigrateCommentVariableInstanceTest.
  */
 
-namespace Drupal\migrate_drupal\Tests\d6;
+namespace Drupal\comment\Tests\d6;
+
+use Drupal\migrate_drupal\Tests\d6\MigrateDrupal6TestBase;
 
 /**
  * Upgrade comment variables to field.instance.node.*.comment.yml.
  *
- * @group migrate_drupal
+ * @group comment
  */
 class MigrateCommentVariableInstanceTest extends MigrateDrupal6TestBase {
 
diff --git a/core/modules/migrate_drupal/tests/src/Unit/source/d6/CommentSourceWithHighWaterTest.php b/core/modules/comment/tests/src/Unit/Plugin/migrate/source/d6/CommentSourceWithHighWaterTest.php
similarity index 70%
rename from core/modules/migrate_drupal/tests/src/Unit/source/d6/CommentSourceWithHighWaterTest.php
rename to core/modules/comment/tests/src/Unit/Plugin/migrate/source/d6/CommentSourceWithHighWaterTest.php
index 26a7e51..e233b23 100644
--- a/core/modules/migrate_drupal/tests/src/Unit/source/d6/CommentSourceWithHighWaterTest.php
+++ b/core/modules/comment/tests/src/Unit/Plugin/migrate/source/d6/CommentSourceWithHighWaterTest.php
@@ -2,15 +2,15 @@
 
 /**
  * @file
- * Contains \Drupal\Tests\migrate_drupal\Unit\source\d6\CommentSourceWithHighWaterTest.
+ * Contains \Drupal\Tests\comment\Unit\Plugin\migrate\source\d6\CommentSourceWithHighWaterTest.
  */
 
-namespace Drupal\Tests\migrate_drupal\Unit\source\d6;
+namespace Drupal\Tests\comment\Unit\Plugin\migrate\source\d6;
 
 /**
  * Tests the Drupal 6 comment source w/ high water handling.
  *
- * @group migrate_drupal
+ * @group comment
  */
 class CommentSourceWithHighWaterTest extends CommentTestBase {
 
diff --git a/core/modules/comment/tests/src/Unit/Plugin/migrate/source/d6/CommentTest.php b/core/modules/comment/tests/src/Unit/Plugin/migrate/source/d6/CommentTest.php
new file mode 100644
index 0000000..b857259
--- /dev/null
+++ b/core/modules/comment/tests/src/Unit/Plugin/migrate/source/d6/CommentTest.php
@@ -0,0 +1,17 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\comment\Unit\Plugin\migrate\source\d6\CommentTest.
+ */
+
+namespace Drupal\Tests\comment\Unit\Plugin\migrate\source\d6;
+
+/**
+ * Tests D6 comment source plugin.
+ *
+ * @group comment
+ */
+class CommentTest extends CommentTestBase {
+
+}
diff --git a/core/modules/migrate_drupal/tests/src/Unit/source/d6/CommentTestBase.php b/core/modules/comment/tests/src/Unit/Plugin/migrate/source/d6/CommentTestBase.php
similarity index 90%
rename from core/modules/migrate_drupal/tests/src/Unit/source/d6/CommentTestBase.php
rename to core/modules/comment/tests/src/Unit/Plugin/migrate/source/d6/CommentTestBase.php
index 0b8f403..d7dc31f 100644
--- a/core/modules/migrate_drupal/tests/src/Unit/source/d6/CommentTestBase.php
+++ b/core/modules/comment/tests/src/Unit/Plugin/migrate/source/d6/CommentTestBase.php
@@ -2,10 +2,10 @@
 
 /**
  * @file
- * Contains \Drupal\Tests\migrate_drupal\Unit\source\d6\CommentTestBase.
+ * Contains \Drupal\Tests\comment\Unit\Plugin\migrate\source\d6\CommentTestBase.
  */
 
-namespace Drupal\Tests\migrate_drupal\Unit\source\d6;
+namespace Drupal\Tests\comment\Unit\Plugin\migrate\source\d6;
 
 use Drupal\Tests\migrate\Unit\MigrateSqlSourceTestCase;
 
@@ -16,7 +16,7 @@
 
   // The plugin system is not working during unit testing so the source plugin
   // class needs to be manually specified.
-  const PLUGIN_CLASS = 'Drupal\migrate_drupal\Plugin\migrate\source\d6\Comment';
+  const PLUGIN_CLASS = 'Drupal\comment\Plugin\migrate\source\d6\Comment';
 
   // The fake Migration configuration entity.
   protected $migrationConfiguration = array(
diff --git a/core/modules/migrate_drupal/tests/src/Unit/source/d6/CommentTest.php b/core/modules/migrate_drupal/tests/src/Unit/source/d6/CommentTest.php
deleted file mode 100644
index 660ae4a..0000000
--- a/core/modules/migrate_drupal/tests/src/Unit/source/d6/CommentTest.php
+++ /dev/null
@@ -1,17 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Tests\migrate_drupal\Unit\source\d6\CommentTest.
- */
-
-namespace Drupal\Tests\migrate_drupal\Unit\source\d6;
-
-/**
- * Tests D6 comment source plugin.
- *
- * @group migrate_drupal
- */
-class CommentTest extends CommentTestBase {
-
-}