a few small fixes
diff --git a/tests/hazmat/primitives/test_hkdf.py b/tests/hazmat/primitives/test_hkdf.py
index 989709c..367addc 100644
--- a/tests/hazmat/primitives/test_hkdf.py
+++ b/tests/hazmat/primitives/test_hkdf.py
@@ -14,6 +14,7 @@
from __future__ import absolute_import, division, print_function
import pytest
+
import six
from cryptography.exceptions import (
diff --git a/tests/hazmat/primitives/twofactor/test_hotp.py b/tests/hazmat/primitives/twofactor/test_hotp.py
index 7692a08..4bb7c6b 100644
--- a/tests/hazmat/primitives/twofactor/test_hotp.py
+++ b/tests/hazmat/primitives/twofactor/test_hotp.py
@@ -21,7 +21,8 @@
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.hashes import MD5, SHA1
from cryptography.hazmat.primitives.twofactor.hotp import HOTP
-from tests.utils import load_nist_vectors, load_vectors_from_file
+
+from ....utils import load_nist_vectors, load_vectors_from_file
vectors = load_vectors_from_file(
"twofactor/rfc-4226.txt", load_nist_vectors)
diff --git a/tests/hazmat/primitives/twofactor/test_totp.py b/tests/hazmat/primitives/twofactor/test_totp.py
index 0b10c96..d5b0a8e 100644
--- a/tests/hazmat/primitives/twofactor/test_totp.py
+++ b/tests/hazmat/primitives/twofactor/test_totp.py
@@ -18,7 +18,8 @@
from cryptography.exceptions import InvalidToken, UnsupportedInterface
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.twofactor.totp import TOTP
-from tests.utils import load_nist_vectors, load_vectors_from_file
+
+from ....utils import load_nist_vectors, load_vectors_from_file
vectors = load_vectors_from_file(
"twofactor/rfc-6238.txt", load_nist_vectors)
diff --git a/tests/utils.py b/tests/utils.py
index 81a86df..79996b6 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -17,6 +17,7 @@
import os
import pytest
+
import six