diff --git a/test/write_flash.c b/test/write_flash.c
index ebd0fb7..6a92d4b 100644
--- a/test/write_flash.c
+++ b/test/write_flash.c
@@ -40,7 +40,7 @@
 {
 	int rc;
 
-	rc = tmpf_init(tmp, "flashXXXXXX");
+	rc = tmpf_init(tmp, "flash-store.XXXXXX");
 	if (rc < 0)
 		return NULL;