diff --git a/metropolis/cli/metroctl/test/main_test.go b/metropolis/cli/metroctl/test/main_test.go
index e02f9c1..e1ca606 100644
--- a/metropolis/cli/metroctl/test/main_test.go
+++ b/metropolis/cli/metroctl/test/main_test.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package test
 
 import (