diff --git a/conanfile.py b/conanfile.py
index 3d869d831b..b859944a89 100644
--- a/conanfile.py
+++ b/conanfile.py
@@ -1,6 +1,5 @@
 from conans import ConanFile
 from conans.tools import os_info
-from conans.model.version import Version
 
 class Exiv2Conan(ConanFile):
     settings = 'os', 'compiler', 'build_type', 'arch'
diff --git a/doc/templates/gen.py b/doc/templates/gen.py
index afc390d18a..7e386d0a72 100755
--- a/doc/templates/gen.py
+++ b/doc/templates/gen.py
@@ -1,4 +1,9 @@
 #! /usr/bin/env python
+import sys
+import os
+import re
+import time
+
 # ----------------------------------------------------------------------
 # Settings
 vardir = "."
@@ -28,11 +33,6 @@ def last_modified(text):
 
 # ----------------------------------------------------------------------
 # main
-import sys
-import os
-import re
-import time
-
 # Check command line arguments
 if len(sys.argv) == 1:
    usage()
@@ -44,7 +44,8 @@ def last_modified(text):
 # Get a list of all variables (files in the form __*__) from vardir 
 vars = os.listdir(vardir)
 for i in range(len(vars)-1, -1, -1):
-   if re.match("^__.*__$", vars[i]): continue
+   if re.match("^__.*__$", vars[i]):
+       continue
    del vars[i]
 vars.sort()
 
diff --git a/tests/bash_tests/testcases.py b/tests/bash_tests/testcases.py
index 437f900e3e..df69a2e8c0 100644
--- a/tests/bash_tests/testcases.py
+++ b/tests/bash_tests/testcases.py
@@ -2,9 +2,9 @@
 import re
 import unittest
 
+from importlib.util import find_spec
 from system_tests import BT
 
-
 class TestCases(unittest.TestCase):
 
 
@@ -368,25 +368,25 @@ def exiv2_test(self):
         out += BT.Executer('exiv2 -u -h')
 
         out += '\n\nAdjust -------------------------------------------------------------------'
-        out += BT.Executer('exiv2 -u -v -a-12:01:01 adjust  {images_1_str}', vars(), assert_returncode=[253])
+        out += BT.Executer('exiv2 -u -v -a-12:01:01 adjust  {}'.format(images_1_str), vars(), assert_returncode=[253])
 
         out += '\nRename -------------------------------------------------------------------'
-        out += BT.Executer('exiv2 -u -vf rename             {images_1_str}', vars(), assert_returncode=[253])
+        out += BT.Executer('exiv2 -u -vf rename             {}'.format(images_1_str), vars(), assert_returncode=[253])
 
         out += '\nPrint --------------------------------------------------------------------'
-        out += BT.Executer('exiv2 -u -v print               {images_2_str}', vars(), assert_returncode=[253])
+        out += BT.Executer('exiv2 -u -v print               {}'.format(images_2_str), vars(), assert_returncode=[253])
         out += ''
-        out += BT.Executer('exiv2 -u -v -b -pt print        {images_2_str}', vars())
-        e    = BT.Executer('exiv2 -u -v -b -pt print        {images_2_str}', vars(), redirect_stderr_to_stdout=False, decode_output=False)
+        out += BT.Executer('exiv2 -u -v -b -pt print        {}'.format(images_2_str), vars())
+        e    = BT.Executer('exiv2 -u -v -b -pt print        {}'.format(images_2_str), vars(), redirect_stderr_to_stdout=False, decode_output=False)
         BT.save(e.stdout, 'iii')
         out += e.stderr.decode()
 
         out += '\nExtract Exif data --------------------------------------------------------'
-        out += BT.Executer('exiv2 -u -vf extract            {images_2_str}', vars())
+        out += BT.Executer('exiv2 -u -vf extract            {}'.format(images_2_str), vars())
 
         out += '\nExtract Thumbnail --------------------------------------------------------'
-        out += BT.Executer('exiv2 -u -vf -et extract        {images_2_str}', vars(), assert_returncode=[253])
-        e    = BT.Executer('exiv2 -u -v -b -pt print        {images_3_str}', vars(), redirect_stderr_to_stdout=False, decode_output=False)
+        out += BT.Executer('exiv2 -u -vf -et extract        {}'.format(images_2_str), vars(), assert_returncode=[253])
+        e    = BT.Executer('exiv2 -u -v -b -pt print        {}'.format(images_3_str), vars(), redirect_stderr_to_stdout=False, decode_output=False)
         BT.save(e.stdout, 'jjj')
         out += e.stderr.decode()
 
@@ -1013,9 +1013,7 @@ def preview_test(self):
     def stdin_test(self):
         return # temporarily disable
         # Test driver for stdin
-        try:
-            import lxml
-        except ModuleNotFoundError:
+        if find_spec('lxml') is None:
             print('Skipped. Because it misses module lxml. Please install: `pip install lxml`')
             return
 
@@ -1334,8 +1332,8 @@ def xmpparser_test(self):
             out += BT.diff(img, img + '-new')
 
         xmp = 'xmpsdk.xmp'
-        BT.save(BT.Executer('xmpparse {xmp}'    , vars()).stdout, 't1')
-        BT.save(BT.Executer('xmpparse {xmp}-new', vars()).stdout, 't2')
+        BT.save(BT.Executer('xmpparse {}'.format(xmp), vars()).stdout, 't1')
+        BT.save(BT.Executer('xmpparse {}-new'.format(xmp), vars()).stdout, 't2')
         out += BT.diff('t1', 't2')
 
         out += BT.Executer('xmpsample')
diff --git a/tests/bash_tests/utils.py b/tests/bash_tests/utils.py
index 3a3012c3b9..e0fb6afe9f 100644
--- a/tests/bash_tests/utils.py
+++ b/tests/bash_tests/utils.py
@@ -364,8 +364,8 @@ def start(self):
             with request.urlopen('http://127.0.0.1:{}'.format(self.port), timeout=3) as f:
                 if f.status != 200:
                     raise RuntimeError()
-        except:
-            raise RuntimeError('Failed to run the HTTP server')
+        except Exception as e:
+            raise RuntimeError('Failed to run the HTTP server: {}'.format(e))
         log.info('The HTTP server started')
 
     def stop(self):
@@ -504,8 +504,8 @@ def run(self):
                 except subprocess.TimeoutExpired:
                     self.subprocess.kill()
                     output  = self.subprocess.communicate()
-        except:
-            raise RuntimeError('Failed to execute: {}'.format(self.args))
+        except Exception as e:
+            raise RuntimeError('Failed to execute {}: {}'.format(self.args, e))
         output          = [i or b'' for i in output]
         output          = [i.rstrip(b'\r\n').rstrip(b'\n') for i in output] # Remove the last line break of the output
 
@@ -556,7 +556,7 @@ def __str__(self):
     def __add__(self, other):
         if isinstance(other, Executer):
             other = other.stdout
-        if other != None:
+        if other is not None:
             self.lines.append(str(other))
         return self
 
@@ -605,7 +605,7 @@ def copyTest(num, src, good):
     src_file    = os.path.join(Config.data_dir, src)
     good_file   = os.path.join(Config.data_dir, '{}.c{}gd'.format(good, num))
     copyTestFile(good, test_file)
-    Executer('metacopy -a {src_file} {test_file}', vars())
+    Executer('metacopy -a {} {}'.format(src_file, test_file), vars())
     return diffCheck(good_file, test_file, in_bytes=True)
 
 
@@ -614,7 +614,7 @@ def iptcTest(num, src, good):
     src_file    = os.path.join(Config.data_dir, src)
     good_file   = os.path.join(Config.data_dir, '{}.i{}gd'.format(good, num))
     copyTestFile(good, test_file)
-    Executer('metacopy -ip {src_file} {test_file}', vars())
+    Executer('metacopy -ip {} {}'.format(src_file, test_file), vars())
     return diffCheck(good_file, test_file, in_bytes=True)
 
 
@@ -624,7 +624,7 @@ def printTest(filename):
     good_file   = os.path.join(Config.data_dir, filename + '.ipgd')
     copyTestFile(filename, test_file)
 
-    e           = Executer('iptcprint {src_file}', vars(), assert_returncode=None, decode_output=False)
+    e           = Executer('iptcprint {}'.format(src_file), vars(), assert_returncode=None, decode_output=False)
     stdout      = e.stdout.replace(Config.data_dir.replace(os.path.sep, '/').encode(), b'../data') # Ignore the difference of data_dir on Windows
     save(stdout + b'\n', test_file)
 
@@ -743,8 +743,8 @@ def runTest(cmd,raw=False):
                 print('{} returncode = {}'.format(cmd, p.returncode))
             # Split the output by newline
             out = stdout.decode('utf-8').replace('\r', '').rstrip('\n').split('\n')
-        except:
-            print('** {} died **'.format(cmd))
+        except Exception as e:
+            print('** {} died: {} **'.format(cmd, e))
 
     return out
 
@@ -758,7 +758,7 @@ def verbose_version(verbose=False):
         kv = line.rstrip().split('=')
         if len(kv)  == 2:
             key, val = kv
-            if not key in vv:
+            if key not in vv:
                 vv[key] = val
             elif isinstance(vv[key], list):
                 vv[key].append(val)
diff --git a/tests/bugfixes/github/test_issue_1097.py b/tests/bugfixes/github/test_issue_1097.py
index f2b4d01ac2..a7dc0b5627 100644
--- a/tests/bugfixes/github/test_issue_1097.py
+++ b/tests/bugfixes/github/test_issue_1097.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path
 
 
 class InfiniteRecursionInCiffDirectoryReadDirectory(metaclass=CaseMeta):
diff --git a/tests/bugfixes/github/test_issue_1099.py b/tests/bugfixes/github/test_issue_1099.py
index 8635219a08..b3bc10bd2d 100644
--- a/tests/bugfixes/github/test_issue_1099.py
+++ b/tests/bugfixes/github/test_issue_1099.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path
 
 
 class EmptyValueInCommandFile(metaclass=CaseMeta):
diff --git a/tests/bugfixes/github/test_issue_1805.py b/tests/bugfixes/github/test_issue_1805.py
index 12ac83014b..6696d6e778 100644
--- a/tests/bugfixes/github/test_issue_1805.py
+++ b/tests/bugfixes/github/test_issue_1805.py
@@ -2,7 +2,7 @@
 
 import unittest
 import system_tests
-from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, check_no_ASAN_UBSAN_errors
 
 # Check that `exiv2 -pr` works for different file types.
 # ExifTool has a list of markers that appear in the headers:
diff --git a/tests/bugfixes/github/test_issue_1812.py b/tests/bugfixes/github/test_issue_1812.py
index 803b9e1934..f8b75b72c9 100644
--- a/tests/bugfixes/github/test_issue_1812.py
+++ b/tests/bugfixes/github/test_issue_1812.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path
 
 
 class OutOfMemoryInJp2ImageReadMetadata(metaclass=CaseMeta):
diff --git a/tests/bugfixes/github/test_issue_1819.py b/tests/bugfixes/github/test_issue_1819.py
index 10f2500cfe..5f2ce1f1f1 100644
--- a/tests/bugfixes/github/test_issue_1819.py
+++ b/tests/bugfixes/github/test_issue_1819.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, CopyTmpFiles, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path
 
 class EmptyStringXmpTextValueRead(metaclass=CaseMeta):
     """
diff --git a/tests/bugfixes/github/test_issue_1827.py b/tests/bugfixes/github/test_issue_1827.py
index 3f9c4eaf3f..c944a1eca3 100644
--- a/tests/bugfixes/github/test_issue_1827.py
+++ b/tests/bugfixes/github/test_issue_1827.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, CopyTmpFiles, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
 
 class ExposureTimeCastDoubleToLong(metaclass=CaseMeta):
     """
diff --git a/tests/bugfixes/github/test_issue_1830.py b/tests/bugfixes/github/test_issue_1830.py
index 99e047fb9c..2a59d927b0 100644
--- a/tests/bugfixes/github/test_issue_1830.py
+++ b/tests/bugfixes/github/test_issue_1830.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, CopyTmpFiles, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
 
 class ValueTypeFloatToLong(metaclass=CaseMeta):
     """
diff --git a/tests/bugfixes/github/test_issue_1941.py b/tests/bugfixes/github/test_issue_1941.py
index f4da62daba..a5318d278a 100644
--- a/tests/bugfixes/github/test_issue_1941.py
+++ b/tests/bugfixes/github/test_issue_1941.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
 import system_tests
-from system_tests import CaseMeta, CopyTmpFiles, path
+from system_tests import CaseMeta
 
 class TestNikonFl7GroupWithFlash(metaclass=CaseMeta):
 
diff --git a/tests/bugfixes/github/test_issue_2339.py b/tests/bugfixes/github/test_issue_2339.py
index b9e63ced9c..a2c24fdf93 100644
--- a/tests/bugfixes/github/test_issue_2339.py
+++ b/tests/bugfixes/github/test_issue_2339.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta
 
 class issue_2339_printDegrees_integer_overflow(metaclass=CaseMeta):
     url      = "https://github.com/Exiv2/exiv2/issues/2339"
diff --git a/tests/bugfixes/github/test_issue_2352.py b/tests/bugfixes/github/test_issue_2352.py
index c48b86e0ca..c3114327b9 100644
--- a/tests/bugfixes/github/test_issue_2352.py
+++ b/tests/bugfixes/github/test_issue_2352.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta
 
 class issue_2352_floatToRationalCast_integer_overflow(metaclass=CaseMeta):
     url      = "https://github.com/Exiv2/exiv2/issues/2352"
diff --git a/tests/bugfixes/github/test_issue_2366.py b/tests/bugfixes/github/test_issue_2366.py
index e7c26f3b30..e7111d593a 100644
--- a/tests/bugfixes/github/test_issue_2366.py
+++ b/tests/bugfixes/github/test_issue_2366.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta
 
 class issue_2366_QuickTimeVideo_userDataDecoder_buffer_overflow(metaclass=CaseMeta):
     url      = "https://github.com/Exiv2/exiv2/issues/2366"
diff --git a/tests/bugfixes/github/test_issue_2376.py b/tests/bugfixes/github/test_issue_2376.py
index 2afdbc9657..af1a0d0379 100644
--- a/tests/bugfixes/github/test_issue_2376.py
+++ b/tests/bugfixes/github/test_issue_2376.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta
 
 class issue_2376_QuickTimeVideo_userDataDecoder_null_deref(metaclass=CaseMeta):
     url      = "https://github.com/Exiv2/exiv2/issues/2376"
diff --git a/tests/bugfixes/github/test_issue_2377.py b/tests/bugfixes/github/test_issue_2377.py
index 010a46685c..c328624fbb 100644
--- a/tests/bugfixes/github/test_issue_2377.py
+++ b/tests/bugfixes/github/test_issue_2377.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta
 
 class issue_2377_QuickTimeVideo_userDataDecoder_buffer_overflow(metaclass=CaseMeta):
     url      = "https://github.com/Exiv2/exiv2/issues/2377"
diff --git a/tests/bugfixes/github/test_issue_2383.py b/tests/bugfixes/github/test_issue_2383.py
index f71f519831..cd3e99abf1 100644
--- a/tests/bugfixes/github/test_issue_2383.py
+++ b/tests/bugfixes/github/test_issue_2383.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta
 
 class issue_2383_QuickTimeVideo_userDataDecoder_null_deref(metaclass=CaseMeta):
     url      = "https://github.com/Exiv2/exiv2/issues/2383"
diff --git a/tests/bugfixes/github/test_issue_2393.py b/tests/bugfixes/github/test_issue_2393.py
index 5b37dd3550..438d635bc4 100644
--- a/tests/bugfixes/github/test_issue_2393.py
+++ b/tests/bugfixes/github/test_issue_2393.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta
 
 class issue_2393_QuickTimeVideo_multipleEntriesDecoder_long_running(metaclass=CaseMeta):
     url      = "https://github.com/Exiv2/exiv2/issues/2393"
diff --git a/tests/bugfixes/github/test_issue_2403.py b/tests/bugfixes/github/test_issue_2403.py
index 0144590ca5..390f48e618 100644
--- a/tests/bugfixes/github/test_issue_2403.py
+++ b/tests/bugfixes/github/test_issue_2403.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, CopyTmpFiles, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, CopyTmpFiles
 @CopyTmpFiles("$data_path/issue_2403_poc.exv")
 
 class checkIconvSegFault(metaclass=CaseMeta):
diff --git a/tests/bugfixes/github/test_issue_2423.py b/tests/bugfixes/github/test_issue_2423.py
index 0c633cf681..1b3171e7e7 100644
--- a/tests/bugfixes/github/test_issue_2423.py
+++ b/tests/bugfixes/github/test_issue_2423.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta
 
 class issue_2423_QuickTimeVideo_sampleDesc_long_running(metaclass=CaseMeta):
     url      = "https://github.com/Exiv2/exiv2/issues/2423"
diff --git a/tests/bugfixes/github/test_issue_646.py b/tests/bugfixes/github/test_issue_646.py
index b836d43298..76bdb31318 100644
--- a/tests/bugfixes/github/test_issue_646.py
+++ b/tests/bugfixes/github/test_issue_646.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, path
+from system_tests import CaseMeta
 
 class Fix646_NikonAF22(metaclass=CaseMeta):
 
diff --git a/tests/bugfixes/github/test_issue_841.py b/tests/bugfixes/github/test_issue_841.py
index 14ba1430f4..3106d8da94 100644
--- a/tests/bugfixes/github/test_issue_841.py
+++ b/tests/bugfixes/github/test_issue_841.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path
 
 
 class InvalidDataLocationInCiffComponentDoRead(metaclass=CaseMeta):
diff --git a/tests/bugfixes/github/test_issue_g44w_q3vm_gwjq.py b/tests/bugfixes/github/test_issue_g44w_q3vm_gwjq.py
index cf17b65d5d..9401083621 100644
--- a/tests/bugfixes/github/test_issue_g44w_q3vm_gwjq.py
+++ b/tests/bugfixes/github/test_issue_g44w_q3vm_gwjq.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, CopyTmpFiles, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
 import unittest
 
 @unittest.skip("Skipping test using option -pR (only for Debug mode)")
diff --git a/tests/bugfixes/github/test_issue_ghsa_583f_w9pm_99r2.py b/tests/bugfixes/github/test_issue_ghsa_583f_w9pm_99r2.py
index 71a975cf3f..c5797771da 100644
--- a/tests/bugfixes/github/test_issue_ghsa_583f_w9pm_99r2.py
+++ b/tests/bugfixes/github/test_issue_ghsa_583f_w9pm_99r2.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path
 
 class Jp2ImagePrintStructureICC(metaclass=CaseMeta):
     """
diff --git a/tests/bugfixes/github/test_issue_ghsa_crmj_qh74_2r36.py b/tests/bugfixes/github/test_issue_ghsa_crmj_qh74_2r36.py
index 704e624e93..79097c782f 100644
--- a/tests/bugfixes/github/test_issue_ghsa_crmj_qh74_2r36.py
+++ b/tests/bugfixes/github/test_issue_ghsa_crmj_qh74_2r36.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, CopyTmpFiles, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path
 
 class QuickTimeVideoNikonTagsDecoderOutOfBoundsRead(metaclass=CaseMeta):
     """
diff --git a/tests/bugfixes/github/test_issue_ghsa_g9xm_7538_mq8w.py b/tests/bugfixes/github/test_issue_ghsa_g9xm_7538_mq8w.py
index 2ff1d4ecc5..6770ce2248 100644
--- a/tests/bugfixes/github/test_issue_ghsa_g9xm_7538_mq8w.py
+++ b/tests/bugfixes/github/test_issue_ghsa_g9xm_7538_mq8w.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, CopyTmpFiles, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
 
 class QuickTimeVideoNikonTagsDecoderOutOfBoundsRead(metaclass=CaseMeta):
     """
diff --git a/tests/bugfixes/github/test_issue_ghsa_h9x9_4f77_336w.py b/tests/bugfixes/github/test_issue_ghsa_h9x9_4f77_336w.py
index d8c01d201b..101ef34d22 100644
--- a/tests/bugfixes/github/test_issue_ghsa_h9x9_4f77_336w.py
+++ b/tests/bugfixes/github/test_issue_ghsa_h9x9_4f77_336w.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, CopyTmpFiles, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
 
 class Jp2ImageEncodeJp2HeaderOutOfBoundsRead2(metaclass=CaseMeta):
     """
diff --git a/tests/bugfixes/github/test_issue_ghsa_m479_7frc_gqqg.py b/tests/bugfixes/github/test_issue_ghsa_m479_7frc_gqqg.py
index 204bd31bd7..a719b25506 100644
--- a/tests/bugfixes/github/test_issue_ghsa_m479_7frc_gqqg.py
+++ b/tests/bugfixes/github/test_issue_ghsa_m479_7frc_gqqg.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path
 
 class ImagePrintIFDStructure(metaclass=CaseMeta):
     """
diff --git a/tests/bugfixes/github/test_issue_ghsa_mxw9_qx4c_6m8v.py b/tests/bugfixes/github/test_issue_ghsa_mxw9_qx4c_6m8v.py
index 76e16eca65..f750dc1414 100644
--- a/tests/bugfixes/github/test_issue_ghsa_mxw9_qx4c_6m8v.py
+++ b/tests/bugfixes/github/test_issue_ghsa_mxw9_qx4c_6m8v.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, CopyTmpFiles, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, CopyTmpFiles, path
 @CopyTmpFiles("$data_path/issue_ghsa_mxw9_qx4c_6m8v_poc.jp2")
 
 class Jp2ImageEncodeJp2HeaderOutOfBoundsRead2(metaclass=CaseMeta):
diff --git a/tests/bugfixes/github/test_issue_ghsa_v5g7_46xf_h728.py b/tests/bugfixes/github/test_issue_ghsa_v5g7_46xf_h728.py
index b65a58e347..c1efd73532 100644
--- a/tests/bugfixes/github/test_issue_ghsa_v5g7_46xf_h728.py
+++ b/tests/bugfixes/github/test_issue_ghsa_v5g7_46xf_h728.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from system_tests import CaseMeta, CopyTmpFiles, path, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path
 
 class Jp2ImageEncodeJp2HeaderOutOfBoundsRead2(metaclass=CaseMeta):
     """
diff --git a/tests/bugfixes/github/test_pr_1979.py b/tests/bugfixes/github/test_pr_1979.py
index fae3e21942..6f97974574 100644
--- a/tests/bugfixes/github/test_pr_1979.py
+++ b/tests/bugfixes/github/test_pr_1979.py
@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 
-import system_tests
-from system_tests import CaseMeta, path, CopyTmpFiles, check_no_ASAN_UBSAN_errors
+from system_tests import CaseMeta, path
 
 class TestExiv2ExtractThumbnailToStdout(metaclass=CaseMeta):
     """
diff --git a/tests/bugfixes/github/test_pr_1994.py b/tests/bugfixes/github/test_pr_1994.py
index 4a6c7ff134..2d4905a4b6 100644
--- a/tests/bugfixes/github/test_pr_1994.py
+++ b/tests/bugfixes/github/test_pr_1994.py
@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 
-import system_tests
 from system_tests import CaseMeta, path
 
 class TestAddModelsForNikonFl3(metaclass=CaseMeta):
diff --git a/tests/bugfixes/github/test_pr_1999.py b/tests/bugfixes/github/test_pr_1999.py
index ef6e4b6492..0a32663be4 100644
--- a/tests/bugfixes/github/test_pr_1999.py
+++ b/tests/bugfixes/github/test_pr_1999.py
@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 
-import system_tests
 from system_tests import CaseMeta, path
 
 class TestXmpDateTimeSetting(metaclass=CaseMeta):
diff --git a/tests/bugfixes/github/test_pr_2000.py b/tests/bugfixes/github/test_pr_2000.py
index e77191cef6..8de1931872 100644
--- a/tests/bugfixes/github/test_pr_2000.py
+++ b/tests/bugfixes/github/test_pr_2000.py
@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 
-import system_tests
 from system_tests import CaseMeta, path, check_no_ASAN_UBSAN_errors
 
 class TestVerboseExtractXmpSidecarToStdout(metaclass=CaseMeta):
diff --git a/tests/bugfixes/github/test_pr_2068.py b/tests/bugfixes/github/test_pr_2068.py
index d25c1860b9..0affc954b6 100644
--- a/tests/bugfixes/github/test_pr_2068.py
+++ b/tests/bugfixes/github/test_pr_2068.py
@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 
-import system_tests
 from system_tests import CaseMeta, path
 
 class TestVerboseExtractStdoutMultiFile(metaclass=CaseMeta):
diff --git a/tests/lens_tests/test_canon_lenses.py b/tests/lens_tests/test_canon_lenses.py
index a67597bd3d..ba41acbfb3 100644
--- a/tests/lens_tests/test_canon_lenses.py
+++ b/tests/lens_tests/test_canon_lenses.py
@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-import re
 import os
 import system_tests
 from lens_tests.utils import extract_lenses_from_cpp, make_test_cases, aperture_to_raw_exif
diff --git a/tests/lens_tests/test_config_file.py b/tests/lens_tests/test_config_file.py
index 14b3c41745..b20903978e 100644
--- a/tests/lens_tests/test_config_file.py
+++ b/tests/lens_tests/test_config_file.py
@@ -1,8 +1,6 @@
-import unittest
 import system_tests
 import os
 import shutil
-import sys
 
 
 # copy the example config file into current working directory
diff --git a/tests/lens_tests/utils.py b/tests/lens_tests/utils.py
index 99bfac0be4..0780dc7bfb 100644
--- a/tests/lens_tests/utils.py
+++ b/tests/lens_tests/utils.py
@@ -1,5 +1,4 @@
 import re
-import os
 import logging
 import math
 from itertools import groupby
@@ -153,7 +152,7 @@ def make_test_cases(lenses):
                 **lens["meta"],
                 "id": lens["id"],
                 "desc": lens["desc"],
-                "target": " *OR* ".join([l["desc"] for l in lens_group if lens_is_match(lens["meta"], l["meta"])]),
+                "target": " *OR* ".join([lg["desc"] for lg in lens_group if lens_is_match(lens["meta"], lg["meta"])]),
             }
             for lens in lens_group
         ]
diff --git a/tests/system_tests.py b/tests/system_tests.py
index d3b00f7913..494ce98dfb 100644
--- a/tests/system_tests.py
+++ b/tests/system_tests.py
@@ -724,7 +724,7 @@ def _encode(self, data_in, encode_action, get_err):
         """
         result = None
         for encoding in self.encodings:
-            if encoding == bytes:
+            if encoding is bytes:
                 return data_in
             try:
                 result = encode_action(data_in, encoding)