diff --git a/test/mod/test_util_osrelease.py b/test/mod/test_util_osrelease.py
index 76eed0a2..0b250ebc 100644
--- a/test/mod/test_util_osrelease.py
+++ b/test/mod/test_util_osrelease.py
@@ -10,7 +10,7 @@ from osbuild.util import osrelease
 from .. import test
 
 
-class TestUtilOSRelease(test.TestBase, unittest.TestCase):
+class TestUtilOSRelease(test.TestBase):
     def test_non_existant(self):
         #
         # Verify default os-release value, if no files are given.
diff --git a/test/src/test_pylint.py b/test/src/test_pylint.py
index 1e39f89f..061ef7d6 100644
--- a/test/src/test_pylint.py
+++ b/test/src/test_pylint.py
@@ -10,7 +10,7 @@ from .. import test
 
 
 @unittest.skipUnless(test.TestBase.have_test_checkout(), "no test-checkout access")
-class TestPylint(test.TestBase, unittest.TestCase):
+class TestPylint(test.TestBase):
     def test_pylint(self):
         #
         # Run `pylint` on all python sources. We simply use `find` to locate
diff --git a/test/test.py b/test/test.py
index 78786d84..612fe5bf 100644
--- a/test/test.py
+++ b/test/test.py
@@ -9,12 +9,13 @@ import os
 import subprocess
 import sys
 import tempfile
+import unittest
 
 import osbuild
 from osbuild.util import linux
 
 
-class TestBase():
+class TestBase(unittest.TestCase):
     """Base Class for Tests
 
     This class serves as base for our test infrastructure and provides access
diff --git a/test/test_assemblers.py b/test/test_assemblers.py
index c47f449a..ff0f0d8d 100644
--- a/test/test_assemblers.py
+++ b/test/test_assemblers.py
@@ -11,7 +11,7 @@ import unittest
 from . import test
 
 
-class TestAssemblers(unittest.TestCase, test.TestBase):
+class TestAssemblers(test.TestBase):
     @classmethod
     def setUpClass(cls):
         super().setUpClass()
diff --git a/test/test_stages.py b/test/test_stages.py
index 02f50991..cc91d03c 100644
--- a/test/test_stages.py
+++ b/test/test_stages.py
@@ -8,7 +8,7 @@ import unittest
 from . import test
 
 
-class TestDescriptions(unittest.TestCase, test.TestBase):
+class TestDescriptions(test.TestBase):
 
     def assertTreeDiffsEqual(self, tree_diff1, tree_diff2):
         """