diff --git a/cmd/govulncheck/main_testmode.go b/cmd/govulncheck/main_testmode.go
index 0ac803b..f616b97 100644
--- a/cmd/govulncheck/main_testmode.go
+++ b/cmd/govulncheck/main_testmode.go
@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build testmode
+// +build testmode
 
 package main
 
diff --git a/internal/goversion.go b/internal/goversion.go
index 1475992..c64f4b9 100644
--- a/internal/goversion.go
+++ b/internal/goversion.go
@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build !testmode
+// +build !testmode
 
 package internal
 
diff --git a/internal/goversion_testmode.go b/internal/goversion_testmode.go
index 09c8964..e84c4d8 100644
--- a/internal/goversion_testmode.go
+++ b/internal/goversion_testmode.go
@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build testmode
+// +build testmode
 
 package internal