diff --git a/core/modules/block_content/tests/src/Kernel/Plugin/migrate/source/d6/BoxTest.php b/core/modules/block_content/tests/src/Kernel/Plugin/migrate/source/d6/BoxTest.php
new file mode 100644
index 0000000..cd97a36
--- /dev/null
+++ b/core/modules/block_content/tests/src/Kernel/Plugin/migrate/source/d6/BoxTest.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace Drupal\Tests\block_content\Kernel\Plugin\migrate\source\d6;
+
+use Drupal\Tests\migrate\Kernel\MigrateSqlSourceTestBase;
+
+/**
+ * Tests D6 block boxes source plugin.
+ *
+ * @covers \Drupal\block_content\Plugin\migrate\source\d6\Box
+ * @group block_content
+ */
+class BoxTest extends MigrateSqlSourceTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['block_content', 'migrate_drupal'];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function providerSource() {
+    $tests = [];
+
+    $tests[0][0]['boxes'] = [
+      [
+        'bid' => 1,
+        'body' => '<p>I made some custom content.</p>',
+        'info' => 'Static Block',
+        'format' => 1,
+      ],
+      [
+        'bid' => 2,
+        'body' => '<p>I made some more custom content.</p>',
+        'info' => 'Test Content',
+        'format' => 1,
+      ],
+    ];
+    // The expected results are identical to the source data.
+    $tests[0][1] = $tests[0][0]['boxes'];
+
+    return $tests;
+  }
+
+}
diff --git a/core/modules/block_content/tests/src/Kernel/Plugin/migrate/source/d7/BlockCustomTest.php b/core/modules/block_content/tests/src/Kernel/Plugin/migrate/source/d7/BlockCustomTest.php
new file mode 100644
index 0000000..cf7bd82
--- /dev/null
+++ b/core/modules/block_content/tests/src/Kernel/Plugin/migrate/source/d7/BlockCustomTest.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace Drupal\Tests\block_content\Kernel\Plugin\migrate\source\d7;
+
+use Drupal\Tests\migrate\Kernel\MigrateSqlSourceTestBase;
+
+/**
+ * Tests d7_block_custom source plugin.
+ *
+ * @covers \Drupal\block_content\Plugin\migrate\source\d7\BlockCustom
+ * @group block_content
+ */
+class BlockCustomTest extends MigrateSqlSourceTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['block_content', 'migrate_drupal'];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function providerSource() {
+    $tests = [];
+
+    $tests[0][0]['block_custom'] = [
+      [
+        'bid' => '1',
+        'body' => "I don't feel creative enough to write anything clever here.",
+        'info' => 'Meh',
+        'format' => 'filtered_html',
+      ],
+    ];
+    // The expected results are identical to the source data.
+    $tests[0][1] = $tests[0][0]['block_custom'];
+
+    return $tests;
+  }
+
+}
diff --git a/core/modules/block_content/tests/src/Unit/Plugin/migrate/source/d6/BoxTest.php b/core/modules/block_content/tests/src/Unit/Plugin/migrate/source/d6/BoxTest.php
deleted file mode 100644
index bb4a1ac..0000000
--- a/core/modules/block_content/tests/src/Unit/Plugin/migrate/source/d6/BoxTest.php
+++ /dev/null
@@ -1,46 +0,0 @@
-<?php
-
-namespace Drupal\Tests\block_content\Unit\Plugin\migrate\source\d6;
-
-use Drupal\Tests\migrate\Unit\MigrateSqlSourceTestCase;
-
-/**
- * Tests D6 block boxes source plugin.
- *
- * @group block_content
- */
-class BoxTest extends MigrateSqlSourceTestCase {
-
-  const PLUGIN_CLASS = 'Drupal\block_content\Plugin\migrate\source\d6\Box';
-
-  protected $migrationConfiguration = array(
-    'id' => 'test',
-    'source' => array(
-      'plugin' => 'd6_boxes',
-    ),
-  );
-
-  protected $expectedResults = array(
-    array(
-      'bid' => 1,
-      'body' => '<p>I made some custom content.</p>',
-      'info' => 'Static Block',
-      'format' => 1,
-    ),
-    array(
-      'bid' => 2,
-      'body' => '<p>I made some more custom content.</p>',
-      'info' => 'Test Content',
-      'format' => 1,
-    ),
-  );
-
-  /**
-   * Prepopulate contents with results.
-   */
-  protected function setUp() {
-    $this->databaseContents['boxes'] = $this->expectedResults;
-    parent::setUp();
-  }
-
-}
diff --git a/core/modules/block_content/tests/src/Unit/Plugin/migrate/source/d7/BlockCustomTest.php b/core/modules/block_content/tests/src/Unit/Plugin/migrate/source/d7/BlockCustomTest.php
deleted file mode 100644
index f213296..0000000
--- a/core/modules/block_content/tests/src/Unit/Plugin/migrate/source/d7/BlockCustomTest.php
+++ /dev/null
@@ -1,40 +0,0 @@
-<?php
-
-namespace Drupal\Tests\block_content\Unit\Plugin\migrate\source\d7;
-
-use Drupal\block_content\Plugin\migrate\source\d7\BlockCustom;
-use Drupal\Tests\migrate\Unit\MigrateSqlSourceTestCase;
-
-/**
- * @coversDefaultClass \Drupal\block_content\Plugin\migrate\source\d7\BlockCustom
- * @group block_content
- */
-class BlockCustomTest extends MigrateSqlSourceTestCase {
-
-  const PLUGIN_CLASS = BlockCustom::class;
-
-  protected $migrationConfiguration = array(
-    'id' => 'test',
-    'source' => array(
-      'plugin' => 'd7_block_custom',
-    ),
-  );
-
-  protected $expectedResults = array(
-    array(
-      'bid' => '1',
-      'body' => "I don't feel creative enough to write anything clever here.",
-      'info' => 'Meh',
-      'format' => 'filtered_html',
-    ),
-  );
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    $this->databaseContents['block_custom'] = $this->expectedResults;
-    parent::setUp();
-  }
-
-}