diff --git a/core/modules/migrate/tests/src/Unit/Plugin/migrate/ConfigurablePluginTraitTest.php b/core/modules/migrate/tests/src/Unit/Plugin/migrate/ConfigurablePluginTraitTest.php
index d3e6c4b959..1c59204365 100644
--- a/core/modules/migrate/tests/src/Unit/Plugin/migrate/ConfigurablePluginTraitTest.php
+++ b/core/modules/migrate/tests/src/Unit/Plugin/migrate/ConfigurablePluginTraitTest.php
@@ -34,6 +34,13 @@ public function testConfigurableTrait() {
     ];
     $mock_class->setConfiguration($test_configuration);
     $this->assertArrayEquals($test_configuration, $mock_class->getConfiguration());
+
+    $test_configuration = [
+      0 => 'zero',
+      2 => 'two',
+    ];
+    $mock_class->setConfiguration($test_configuration);
+    $this->assertArrayEquals($test_configuration, $mock_class->getConfiguration());
   }
 
   /**