diff --git a/bin/make_test_files.go b/bin/make_test_files.go
index 805d1424f..6fe5311d0 100644
--- a/bin/make_test_files.go
+++ b/bin/make_test_files.go
@@ -93,7 +93,7 @@ func (d *dir) createDirectories() {
 
 // list the directory heirachy
 func (d *dir) list(path string, output []string) []string {
-	dirPath := path + "/" + d.name
+	dirPath := filepath.Join(path, d.name)
 	output = append(output, dirPath)
 	for _, subDir := range d.children {
 		output = subDir.list(dirPath, output)