diff --git a/setup.cfg b/setup.cfg
index 328d1896..9458d0fe 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -38,7 +38,8 @@ per-file-ignores =
     linkcheck/htmlutil/htmlsoup.py: E402
     linkcheck/parser/__init__.py: E402
     tests/__init__.py: F401
-    
+# E501: line too long
+    tests/test_ftpparse.py: E501
 extend-ignore =
 # https://pep8.readthedocs.org/en/latest/intro.html#error-codes
 # these are ignored by default:
diff --git a/tests/checker/__init__.py b/tests/checker/__init__.py
index 0e647dbe..e7182d60 100644
--- a/tests/checker/__init__.py
+++ b/tests/checker/__init__.py
@@ -68,7 +68,8 @@ class TestLogger(linkcheck.logger._Logger):
         self.diff = []
 
     def normalize(self, result_log):
-        # XXX we assume that each log entry has a URL key, maybe we should add an assert into log_url() to that effect?
+        # XXX we assume that each log entry has a URL key,
+        # maybe we should add an assert into log_url() to that effect?
         # Ensure that log entries are sorted by URL key:
         # - join the result_log items together
         # - split into entries (starting with a URL key)
@@ -289,9 +290,9 @@ class LinkCheckTest(unittest.TestCase):
         linkcheck.director.check_urls(aggregate)
         diff = aggregate.config["logger"].diff
         if diff:
-            l = ["Differences found testing %s" % url]
-            l.extend(x.rstrip() for x in diff[2:])
-            self.fail(os.linesep.join(l))
+            d = ["Differences found testing %s" % url]
+            d.extend(x.rstrip() for x in diff[2:])
+            self.fail(os.linesep.join(d))
 
 
 class MailTest(LinkCheckTest):
diff --git a/tests/checker/ftpserver.py b/tests/checker/ftpserver.py
index 6fd192f7..031f6a43 100644
--- a/tests/checker/ftpserver.py
+++ b/tests/checker/ftpserver.py
@@ -91,7 +91,7 @@ def start_server(host, port):
             ftp.login()
             ftp.close()
             break
-        except:
+        except Exception:
             time.sleep(0.5)
     return port
 
diff --git a/tests/checker/httpserver.py b/tests/checker/httpserver.py
index f4dcf2f0..c5370a7e 100644
--- a/tests/checker/httpserver.py
+++ b/tests/checker/httpserver.py
@@ -52,7 +52,7 @@ class StoppableHttpRequestHandler(SimpleHTTPRequestHandler):
 
 # serve .xhtml files as application/xhtml+xml
 StoppableHttpRequestHandler.extensions_map.update(
-    {".xhtml": "application/xhtml+xml",}
+    {".xhtml": "application/xhtml+xml"}
 )
 
 
@@ -221,7 +221,7 @@ def start_server(handler, https=False):
             conn.request("GET", "/")
             conn.getresponse()
             break
-        except:
+        except Exception:
             time.sleep(0.5)
     return port
 
diff --git a/tests/checker/telnetserver.py b/tests/checker/telnetserver.py
index 24878eb1..1460bd14 100644
--- a/tests/checker/telnetserver.py
+++ b/tests/checker/telnetserver.py
@@ -81,7 +81,7 @@ def start_server(host, port, stop_event):
             client.open(host, port)
             client.write(b"exit\n")
             break
-        except:
+        except Exception:
             time.sleep(0.5)
     return port, t
 
diff --git a/tests/checker/test_http_misc.py b/tests/checker/test_http_misc.py
index 9c3c66d0..c6bd0d80 100644
--- a/tests/checker/test_http_misc.py
+++ b/tests/checker/test_http_misc.py
@@ -27,7 +27,7 @@ class TestHttpMisc(HttpServerTest):
     def test_html_internet(self):
         self.swf_test()
         self.file_test("sitemap.xml")
-    
+
     def test_html(self):
         self.file_test("sitemapindex.xml")
 
diff --git a/tests/checker/test_https.py b/tests/checker/test_https.py
index 26d59525..a3220f4d 100644
--- a/tests/checker/test_https.py
+++ b/tests/checker/test_https.py
@@ -18,7 +18,6 @@ Test https.
 """
 from OpenSSL import crypto
 
-from tests import need_network
 from .httpserver import HttpsServerTest, CookieRedirectHttpRequestHandler
 from .. import get_file
 
diff --git a/tests/checker/test_news.py b/tests/checker/test_news.py
index ba793a33..fbbae9d8 100644
--- a/tests/checker/test_news.py
+++ b/tests/checker/test_news.py
@@ -31,6 +31,7 @@ NNTP_INFO = (
 # Most free NNTP servers are slow, so don't waist a lot of time running those.
 NNTP_TIMEOUT_SECS = 30
 
+
 # disabled for now until some stable news server comes up
 @pytest.mark.skip(reason="disabled for now until some stable news server comes up")
 class TestNews(LinkCheckTest):
diff --git a/tests/test_clamav.py b/tests/test_clamav.py
index b12d515d..4a98e61f 100644
--- a/tests/test_clamav.py
+++ b/tests/test_clamav.py
@@ -55,7 +55,7 @@ class TestClamav(unittest.TestCase):
         acceptable_responses = (
             ["stream: ClamAV-Test-File(2d1206194bd704385e37000be6113f73:781) FOUND\n"],
             [
-                "stream: Clamav.Test.File-6(aa15bcf478d165efd2065190eb473bcb:544) FOUND\n"
+              "stream: Clamav.Test.File-6(aa15bcf478d165efd2065190eb473bcb:544) FOUND\n"
             ],
         )
         self.assertIn(infected, acceptable_responses)
diff --git a/tests/test_containers.py b/tests/test_containers.py
index 8c93000e..a5eb9884 100644
--- a/tests/test_containers.py
+++ b/tests/test_containers.py
@@ -37,6 +37,7 @@ class TestLFUCache(unittest.TestCase):
         self.assertEqual(self.d.uses("a"), 0)
         dummy = self.d["a"]
         self.assertEqual(self.d.uses("a"), 1)
+        del dummy
 
     def test_values(self):
         self.assertTrue(not self.d)
diff --git a/tests/test_dummy.py b/tests/test_dummy.py
index 113f9c1a..bdf4e559 100644
--- a/tests/test_dummy.py
+++ b/tests/test_dummy.py
@@ -33,6 +33,7 @@ class TestDummy(unittest.TestCase):
         dummy = linkcheck.dummy.Dummy("1", "2")
         dummy = linkcheck.dummy.Dummy(a=1, b=2)
         dummy = linkcheck.dummy.Dummy("1", a=None, b=2)
+        del dummy
 
     def test_attributes(self):
         dummy = linkcheck.dummy.Dummy()
diff --git a/tests/test_strformat.py b/tests/test_strformat.py
index 96716234..f17029d4 100644
--- a/tests/test_strformat.py
+++ b/tests/test_strformat.py
@@ -59,13 +59,13 @@ class TestStrFormat(unittest.TestCase):
         # testing width <= 0
         self.assertEqual(wrap(s, -1), s)
         self.assertEqual(wrap(s, 0), s)
-        l = len(os.linesep)
+        n = len(os.linesep)
         gap = " "
         s2 = "11%(gap)s22%(sep)s33%(gap)s44%(sep)s55" % {"sep": os.linesep, "gap": gap}
         # splitting lines
         self.assertEqual(wrap(s2, 2), s)
         # combining lines
-        self.assertEqual(wrap(s, 4 + l), s2)
+        self.assertEqual(wrap(s, 4 + n), s2)
         # misc
         self.assertEqual(wrap(s, -1), s)
         self.assertEqual(wrap(s, 0), s)
@@ -133,7 +133,8 @@ class TestStrFormat(unittest.TestCase):
         self.assertEqual(duration(60 * 60 * 24), "24:00:00")
 
     def test_duration_long(self):
-        duration = lambda s: linkcheck.strformat.strduration_long(s, do_translate=False)
+        def duration(s):
+            return linkcheck.strformat.strduration_long(s, do_translate=False)
         self.assertEqual(duration(-0.5), "-0.50 seconds")
         self.assertEqual(duration(0), "0.00 seconds")
         self.assertEqual(duration(0.9), "0.90 seconds")
diff --git a/tests/test_url.py b/tests/test_url.py
index 3b998e5a..b060af99 100644
--- a/tests/test_url.py
+++ b/tests/test_url.py
@@ -125,7 +125,10 @@ class TestUrl(unittest.TestCase):
         # the no-quote chars
         url = "http://example.com/a*+-();b"
         self.urlnormtest(url, url)
-        url = "http://linkchecker.git.sourceforge.net/git/gitweb.cgi?p=linkchecker/linkchecker;a=blob;f=doc/changelog.txt;hb=HEAD"
+        url = (
+            "http://linkchecker.git.sourceforge.net/git/gitweb.cgi"
+            "?p=linkchecker/linkchecker;a=blob;f=doc/changelog.txt;hb=HEAD"
+        )
         self.urlnormtest(url, url)
         url = "http://www.company.com/path/doc.html?url=/path2/doc2.html?foo=bar"
         self.urlnormtest(url, url)