--- /dev/null
+<?php
+
+namespace Drupal\Tests\file\Kernel\Plugin\migrate\source\d6;
+
+use Drupal\Tests\migrate\Kernel\MigrateSqlSourceTestBase;
+
+/**
+ * Tests D6 d6_upload_instance source plugin.
+ *
+ * @covers \Drupal\file\Plugin\migrate\source\d6\UploadInstance
+ *
+ * @group file
+ */
+class UploadInstanceTest extends MigrateSqlSourceTestBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public static $modules = ['file', 'migrate_drupal'];
+
+ /**
+ * {@inheritdoc}
+ */
+ public function providerSource() {
+ $tests = [];
+
+ // The source data.
+ $tests[0]['source_data']['node_type'] = [
+ [
+ 'type' => 'article',
+ ],
+ [
+ 'type' => 'company',
+ ],
+ ];
+
+ $tests[0]['source_data']['variable'] = [
+ [
+ 'name' => 'upload_article',
+ 'value' => serialize(TRUE),
+ ],
+ [
+ 'name' => 'upload_company',
+ 'value' => serialize(FALSE),
+ ],
+ [
+ 'name' => 'upload_uploadsize_default',
+ 'value' => serialize(16),
+ ],
+ [
+ 'name' => 'upload_extensions_default',
+ 'value' => serialize('txt pdf'),
+ ],
+ ];
+
+ // The expected results.
+ $tests[0]['expected_data'] = [
+ [
+ 'node_type' => 'article',
+ 'max_filesize' => '16MB',
+ 'file_extensions' => 'txt pdf',
+ ],
+ ];
+
+ return $tests;
+ }
+
+}