diff --git a/tests/test_npy2hls.py b/tests/test_npy2hls.py
new file mode 100644
index 0000000000000000000000000000000000000000..39b594c2f08327358727b8912d9e1f8b32806123
--- /dev/null
+++ b/tests/test_npy2hls.py
@@ -0,0 +1,14 @@
+from finn.core.datatype import DataType
+from finn.core.utils import array2hexstring
+
+
+def test_array2hexstring():
+    assert array2hexstring([1, 1, 1, 0], DataType.BINARY, 4) == "e"
+    assert array2hexstring([1, 1, 1, 0], DataType.BINARY, 8) == "0e"
+    assert array2hexstring([1, 1, 1, -1], DataType.BIPOLAR, 8) == "0e"
+    assert array2hexstring([3, 3, 3, 3], DataType.UINT2, 8) == "ff"
+    assert array2hexstring([1, 3, 3, 1], DataType.UINT2, 8) == "7d"
+    assert array2hexstring([1, -1, 1, -1], DataType.INT2, 8) == "77"
+    assert array2hexstring([1, 1, 1, -1], DataType.INT4, 16) == "111f"
+    assert array2hexstring([-1], DataType.FLOAT32, 32) == "bf800000"
+    assert array2hexstring([17.125], DataType.FLOAT32, 32) == "41890000"