diff --git a/tests/test_merkle_set.py b/tests/test_merkle_set.py
index 595abd98..3f42d58c 100644
--- a/tests/test_merkle_set.py
+++ b/tests/test_merkle_set.py
@@ -66,7 +66,7 @@ def check_tree(leafs: List[bytes32]) -> None:
         )
 
     for i in range(256):
-        item = bytes32.fill(i.to_bytes(), fill=b"\x02", align="<")
+        item = bytes32.fill(bytes([i]), fill=b"\x02", align="<")
         py_included, py_proof = py_tree.is_included_already_hashed(item)
         assert not py_included
         ru_included, ru_proof = ru_tree.is_included_already_hashed(item)
diff --git a/tests/test_sized_bytes.py b/tests/test_sized_bytes.py
index a7b8aef1..ec357600 100644
--- a/tests/test_sized_bytes.py
+++ b/tests/test_sized_bytes.py
@@ -29,8 +29,12 @@ def test_fill_not_multiple_raises() -> None:
     with pytest.raises(ValueError):
         bytes8.fill(b"\x00", fill=b"\x01\x01")
 
+
 def test_align_left() -> None:
-    assert bytes8.fill(b"\x01", fill=b"\x02", align="<") == bytes8([1, 2, 2, 2, 2, 2, 2, 2])
+    assert bytes8.fill(b"\x01", fill=b"\x02", align="<") == bytes8(
+        [1, 2, 2, 2, 2, 2, 2, 2]
+    )
+
 
 def test_invalid_alignment() -> None:
     with pytest.raises(ValueError):