diff --git a/tests/test_signatures.py b/tests/test_signatures.py
index 4f7bd105..a6b3805d 100755
--- a/tests/test_signatures.py
+++ b/tests/test_signatures.py
@@ -4,56 +4,62 @@ import hashlib
 import os
 import sys
 import unittest
-from tempfile import TemporaryDirectory
 
 from fdroidserver import common, signatures
 
-from .shared_test_code import TmpCwd
+from .shared_test_code import mkdtemp
 
 basedir = os.path.dirname(__file__)
 
 
 class SignaturesTest(unittest.TestCase):
     def setUp(self):
+        self._td = mkdtemp()
+        self.testdir = self._td.name
+        os.chdir(self.testdir)
+
         common.config = None
         config = common.read_config()
         config['jarsigner'] = common.find_sdk_tools_cmd('jarsigner')
         common.config = config
 
+    def tearDown(self):
+        self._td.cleanup()
+        common.config = None
+
     @unittest.skipIf(sys.byteorder == 'big', "androguard is not ported to big-endian")
     def test_main(self):
         class OptionsFixture:
             APK = [os.path.join(basedir, 'repo', 'com.politedroid_3.apk')]
 
-        with TemporaryDirectory() as tmpdir, TmpCwd(tmpdir):
-            signatures.extract(OptionsFixture)
+        signatures.extract(OptionsFixture)
 
-            # check if extracted signatures are where they are supposed to be
-            # also verify weather if extracted file contain what they should
-            filesAndHashes = (
-                (
-                    os.path.join(
-                        'metadata', 'com.politedroid', 'signatures', '3', 'MANIFEST.MF'
-                    ),
-                    '7dcd83f0c41a75457fd2311bf3c4578f80d684362d74ba8dc52838d353f31cf2',
+        # check if extracted signatures are where they are supposed to be
+        # also verify weather if extracted file contain what they should
+        filesAndHashes = (
+            (
+                os.path.join(
+                    'metadata', 'com.politedroid', 'signatures', '3', 'MANIFEST.MF'
                 ),
-                (
-                    os.path.join(
-                        'metadata', 'com.politedroid', 'signatures', '3', 'RELEASE.RSA'
-                    ),
-                    '883ef3d5a6e0bf69d2a58d9e255a7930f08a49abc38e216ed054943c99c8fdb4',
+                '7dcd83f0c41a75457fd2311bf3c4578f80d684362d74ba8dc52838d353f31cf2',
+            ),
+            (
+                os.path.join(
+                    'metadata', 'com.politedroid', 'signatures', '3', 'RELEASE.RSA'
                 ),
-                (
-                    os.path.join(
-                        'metadata', 'com.politedroid', 'signatures', '3', 'RELEASE.SF'
-                    ),
-                    '99fbb3211ef5d7c1253f3a7ad4836eadc9905103ce6a75916c40de2831958284',
+                '883ef3d5a6e0bf69d2a58d9e255a7930f08a49abc38e216ed054943c99c8fdb4',
+            ),
+            (
+                os.path.join(
+                    'metadata', 'com.politedroid', 'signatures', '3', 'RELEASE.SF'
                 ),
+                '99fbb3211ef5d7c1253f3a7ad4836eadc9905103ce6a75916c40de2831958284',
+            ),
+        )
+        for path, checksum in filesAndHashes:
+            self.assertTrue(
+                os.path.isfile(path),
+                f'check whether {path!r} was extracted correctly.',
             )
-            for path, checksum in filesAndHashes:
-                self.assertTrue(
-                    os.path.isfile(path),
-                    f'check whether {path!r} was extracted correctly.',
-                )
-                with open(path, 'rb') as f:
-                    self.assertEqual(hashlib.sha256(f.read()).hexdigest(), checksum)
+            with open(path, 'rb') as f:
+                self.assertEqual(hashlib.sha256(f.read()).hexdigest(), checksum)