diff --git a/tests/test_utility.py b/tests/test_utility.py
new file mode 100644
index 00000000..02c4364f
--- /dev/null
+++ b/tests/test_utility.py
@@ -0,0 +1,12 @@
+# -*- coding: utf-8 -*-
+
+import numpy as np
+import pytest
+
+import amrex.space3d as amr
+
+def test_concatenate():
+    pltname = amr.concatenate("plt",1000,5)
+    print("--test concatenate --")
+    print("plotfile name", pltname)
+    assert (pltname == "plt01000")