diff --git a/cmd/cloner/cloner.go b/cmd/cloner/cloner.go
index b4e940b2d..db354af3b 100644
--- a/cmd/cloner/cloner.go
+++ b/cmd/cloner/cloner.go
@@ -78,7 +78,11 @@ func main() {
 		w("	return false")
 		w("}")
 	}
-	cloneOutput := pkg.Name + "_clone.go"
+	cloneOutput := pkg.Name + "_clone"
+	if *flagBuildTags == "test" {
+		cloneOutput += "_test"
+	}
+	cloneOutput += ".go"
 	if err := codegen.WritePackageFile("tailscale.com/cmd/cloner", pkg, cloneOutput, it, buf); err != nil {
 		log.Fatal(err)
 	}
diff --git a/cmd/viewer/viewer.go b/cmd/viewer/viewer.go
index 557b6e459..d2be6af66 100644
--- a/cmd/viewer/viewer.go
+++ b/cmd/viewer/viewer.go
@@ -459,7 +459,11 @@ func main() {
 		}
 		genView(buf, it, typ, pkg.Types)
 	}
-	out := pkg.Name + "_view.go"
+	out := pkg.Name + "_view"
+	if *flagBuildTags == "test" {
+		out += "_test"
+	}
+	out += ".go"
 	if err := codegen.WritePackageFile("tailscale/cmd/viewer", pkg, out, it, buf); err != nil {
 		log.Fatal(err)
 	}