diff --git a/Tests/ttLib/sfnt_test.py b/Tests/ttLib/sfnt_test.py
new file mode 100644
index 000000000..2119351d1
--- /dev/null
+++ b/Tests/ttLib/sfnt_test.py
@@ -0,0 +1,8 @@
+from __future__ import print_function, division, absolute_import
+from fontTools.misc.py23 import *
+from fontTools.ttLib.sfnt import calcChecksum
+
+
+def test_calcChecksum():
+    assert calcChecksum(b"abcd") == 1633837924
+    assert calcChecksum(b"abcdxyz") == 3655064932