diff --git a/tests/test_cbook.py b/tests/test_cbook.py
index 8c46692c..91113bb7 100644
--- a/tests/test_cbook.py
+++ b/tests/test_cbook.py
@@ -3,8 +3,6 @@
 # Released under the GNU Public License 3 (or higher, your choice)
 # See the file COPYING for details.
 
-from __future__ import division, absolute_import, print_function
-
 import os.path
 import re
 
diff --git a/tests/test_collections.py b/tests/test_collections.py
index 9877a7d4..120efb3f 100644
--- a/tests/test_collections.py
+++ b/tests/test_collections.py
@@ -4,10 +4,6 @@
 # Released under the GNU Public License 3 (or higher, your choice)
 # See the file COPYING for details.
 
-from __future__ import division, absolute_import, print_function
-
-import six
-
 import pytest
 
 import gromacs
diff --git a/tests/test_config.py b/tests/test_config.py
index 10b42686..641e7a29 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -3,17 +3,12 @@
 # Released under the GNU Public License 3 (or higher, your choice)
 # See the file COPYING for details.
 
-from __future__ import division, absolute_import, print_function
-
 import contextlib
 import os
 import errno
 import sys
 
-if sys.version_info[0] < 3:
-    from ConfigParser import NoOptionError, NoSectionError
-else:
-    from configparser import NoOptionError, NoSectionError
+from configparser import NoOptionError, NoSectionError
 
 import pytest
 
diff --git a/tests/test_core.py b/tests/test_core.py
index f24ec54b..7741f64c 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -4,10 +4,6 @@
 # Released under the GNU Public License 3 (or higher, your choice)
 # See the file COPYING for details.
 
-from __future__ import division, absolute_import, print_function
-
-import six
-
 import os.path
 import pytest
 
@@ -73,10 +69,7 @@ def test_run_with_input(self, command, inp):
     def test_Popen_with_input(self, command, inp):
         po = command.Popen(stdout=False, stderr=False, input=inp)
         inp_string = "\n".join(gromacs.utilities.asiterable(inp)) + "\n"
-        if six.PY2:
-            assert po.input == inp_string.encode("utf-8")
-        else:
-            assert po.input == inp_string
+        assert po.input == inp_string
 
     def test_help_short(self, command, capsys):
         command.help()
diff --git a/tests/test_run.py b/tests/test_run.py
index 12dd64ca..95041dd2 100644
--- a/tests/test_run.py
+++ b/tests/test_run.py
@@ -3,8 +3,6 @@
 # Released under the GNU Public License 3 (or higher, your choice)
 # See the file COPYING for details.
 
-from __future__ import division, absolute_import, print_function
-
 import time
 import pytest
 import os
diff --git a/tests/test_setup.py b/tests/test_setup.py
index 6c657ef9..ba2cfbd6 100644
--- a/tests/test_setup.py
+++ b/tests/test_setup.py
@@ -3,8 +3,6 @@
 # Released under the GNU Public License 3 (or higher, your choice)
 # See the file COPYING for details.
 
-from __future__ import division, absolute_import, print_function
-
 import os.path
 import pytest
 
@@ -68,7 +66,7 @@ def energy_minimize(solvate, low_performance):
             integrator="steep",
             emtol=5000,
             maxwarn=1,
-            **solvate_args
+            **solvate_args,
         )
     return TMPDIR, em_args
 
diff --git a/tests/test_tools.py b/tests/test_tools.py
index e06557bb..e85318b9 100644
--- a/tests/test_tools.py
+++ b/tests/test_tools.py
@@ -3,8 +3,6 @@
 # Released under the GNU Public License 3 (or higher, your choice)
 # See the file COPYING for details.
 
-from __future__ import division, absolute_import, print_function
-
 import pytest
 
 import gromacs
diff --git a/tests/test_utilities.py b/tests/test_utilities.py
index a06cd2e3..5a9475e7 100644
--- a/tests/test_utilities.py
+++ b/tests/test_utilities.py
@@ -3,13 +3,11 @@
 # Released under the GNU Public License 3 (or higher, your choice)
 # See the file COPYING for details.
 
-from __future__ import division, absolute_import, print_function
-
 import os.path
 import pytest
-from six.moves import cPickle as pickle
-from six.moves import StringIO
-from six.moves.collections_abc import Iterable
+import pickle
+from io import StringIO
+from collections.abc import Iterable
 
 import numpy as np
 
diff --git a/tests/test_version.py b/tests/test_version.py
index a067b85d..b03d9858 100644
--- a/tests/test_version.py
+++ b/tests/test_version.py
@@ -13,8 +13,8 @@ def test_version():
     release = gromacs.__version__
     assert isinstance(release, str)
 
+
 def test_version_pep440_like():
     release = gromacs.__version__
     match = re.match(r"\d+\.\d+\.\d+", release)
     assert match, f"Version {release} does not look like MAJOR.MINOR.PATCH..."
-