diff --git a/tests/dictserver.py b/tests/dictserver.py
index ea9f586c44..87a00d61d0 100755
--- a/tests/dictserver.py
+++ b/tests/dictserver.py
@@ -96,7 +96,7 @@ class DictHandler(socketserver.BaseRequestHandler):
                 response_data = "No matches"
 
             # Send back a failure to find.
-            response = "552 {0}\n".format(response_data)
+            response = f"552 {response_data}\n"
             log.debug("[DICT] Responding with %r", response)
             self.request.sendall(response.encode("utf-8"))
 
diff --git a/tests/http/test_11_unix.py b/tests/http/test_11_unix.py
index 115c74f297..9321d71414 100644
--- a/tests/http/test_11_unix.py
+++ b/tests/http/test_11_unix.py
@@ -68,7 +68,7 @@ class UDSFaker:
     def _process(self):
         while self._done is False:
             try:
-                c, client_address = self._socket.accept()
+                c, _client_address = self._socket.accept()
                 try:
                     c.recv(16)
                     c.sendall(b"""HTTP/1.1 200 Ok
diff --git a/tests/http/testenv/caddy.py b/tests/http/testenv/caddy.py
index 399bead7a5..6d79559b7e 100644
--- a/tests/http/testenv/caddy.py
+++ b/tests/http/testenv/caddy.py
@@ -47,7 +47,7 @@ class Caddy:
 
     def __init__(self, env: Env):
         self.env = env
-        self._caddy = os.environ['CADDY'] if 'CADDY' in os.environ else env.caddy
+        self._caddy = os.environ.get('CADDY', env.caddy)
         self._caddy_dir = os.path.join(env.gen_dir, 'caddy')
         self._docs_dir = os.path.join(self._caddy_dir, 'docs')
         self._conf_file = os.path.join(self._caddy_dir, 'Caddyfile')
diff --git a/tests/http/testenv/certs.py b/tests/http/testenv/certs.py
index 81eb09059d..6376a3d445 100644
--- a/tests/http/testenv/certs.py
+++ b/tests/http/testenv/certs.py
@@ -280,8 +280,7 @@ class CertStore:
         with open(cert_file, "wb") as fd:
             fd.write(creds.cert_pem)
             if chain:
-                for c in chain:
-                    fd.write(c.cert_pem)
+                fd.writelines(c.cert_pem for c in chain)
             if pkey_file is None:
                 fd.write(creds.pkey_pem)
         if pkey_file is not None:
@@ -290,8 +289,7 @@ class CertStore:
         with open(comb_file, "wb") as fd:
             fd.write(creds.cert_pem)
             if chain:
-                for c in chain:
-                    fd.write(c.cert_pem)
+                fd.writelines(c.cert_pem for c in chain)
             fd.write(creds.pkey_pem)
         creds.set_files(cert_file, pkey_file, comb_file)
         self._add_credentials(name, creds)
@@ -306,8 +304,7 @@ class CertStore:
             chain = chain[:-1]
         chain_file = os.path.join(self._store_dir, f'{name}-{infix}.pem')
         with open(chain_file, "wb") as fd:
-            for c in chain:
-                fd.write(c.cert_pem)
+            fd.writelines(c.cert_pem for c in chain)
 
     def _add_credentials(self, name: str, creds: Credentials):
         if name not in self._creds_by_name:
@@ -315,14 +312,14 @@ class CertStore:
         self._creds_by_name[name].append(creds)
 
     def get_credentials_for_name(self, name) -> List[Credentials]:
-        return self._creds_by_name[name] if name in self._creds_by_name else []
+        return self._creds_by_name.get(name, [])
 
     def get_cert_file(self, name: str, key_type=None) -> str:
-        key_infix = ".{0}".format(key_type) if key_type is not None else ""
+        key_infix = f".{key_type}" if key_type is not None else ""
         return os.path.join(self._store_dir, f'{name}{key_infix}.cert.pem')
 
     def get_pkey_file(self, name: str, key_type=None) -> str:
-        key_infix = ".{0}".format(key_type) if key_type is not None else ""
+        key_infix = f".{key_type}" if key_type is not None else ""
         return os.path.join(self._store_dir, f'{name}{key_infix}.pkey.pem')
 
     def get_combined_file(self, name: str, key_type=None) -> str:
diff --git a/tests/http/testenv/client.py b/tests/http/testenv/client.py
index 39fd61054d..a2e72237f4 100644
--- a/tests/http/testenv/client.py
+++ b/tests/http/testenv/client.py
@@ -45,7 +45,7 @@ class LocalClient:
         self.env = env
         self._run_env = run_env
         self._timeout = timeout if timeout else env.test_timeout
-        self._curl = os.environ['CURL'] if 'CURL' in os.environ else env.curl
+        self._curl = os.environ.get('CURL', env.curl)
         self._run_dir = run_dir if run_dir else os.path.join(env.gen_dir, name)
         self._stdoutfile = f'{self._run_dir}/stdout'
         self._stderrfile = f'{self._run_dir}/stderr'
diff --git a/tests/http/testenv/curl.py b/tests/http/testenv/curl.py
index f37928471f..7b026e325f 100644
--- a/tests/http/testenv/curl.py
+++ b/tests/http/testenv/curl.py
@@ -627,7 +627,7 @@ class CurlClient:
                  socks_args: Optional[List[str]] = None):
         self.env = env
         self._timeout = timeout if timeout else env.test_timeout
-        self._curl = os.environ['CURL'] if 'CURL' in os.environ else env.curl
+        self._curl = os.environ.get('CURL', env.curl)
         self._run_dir = run_dir if run_dir else os.path.join(env.gen_dir, 'curl')
         self._stdoutfile = f'{self._run_dir}/curl.stdout'
         self._stderrfile = f'{self._run_dir}/curl.stderr'
diff --git a/tests/http/testenv/env.py b/tests/http/testenv/env.py
index 24c2276c1e..0c19d6bd16 100644
--- a/tests/http/testenv/env.py
+++ b/tests/http/testenv/env.py
@@ -914,8 +914,7 @@ class Env:
         s = round((line_length / 10) + 1) * s10
         s = s[0:line_length - 11]
         with open(fpath, "w") as fd:
-            for i in range(int(fsize / line_length)):
-                fd.write(f"{i:09d}-{s}\n")
+            fd.writelines(f"{i:09d}-{s}\n" for i in range(int(fsize / line_length)))
             remain = int(fsize % line_length)
             if remain != 0:
                 i = int(fsize / line_length) + 1
diff --git a/tests/http/testenv/httpd.py b/tests/http/testenv/httpd.py
index c2a0a22b8f..c389a9a56c 100644
--- a/tests/http/testenv/httpd.py
+++ b/tests/http/testenv/httpd.py
@@ -29,6 +29,7 @@ import os
 import shutil
 import socket
 import subprocess
+import textwrap
 import time
 from datetime import datetime, timedelta
 from json import JSONEncoder
@@ -137,8 +138,7 @@ class Httpd:
         env['APACHE_RUN_USER'] = os.environ['USER']
         env['APACHE_LOCK_DIR'] = self._lock_dir
         env['APACHE_CONFDIR'] = self._apache_dir
-        p = subprocess.run(args, stderr=subprocess.PIPE, stdout=subprocess.PIPE,
-                           cwd=self.env.gen_dir,
+        p = subprocess.run(args, capture_output=True, cwd=self.env.gen_dir,
                            input=intext.encode() if intext else None,
                            env=env, check=True)
         start = datetime.now()
@@ -170,7 +170,7 @@ class Httpd:
 
     def start(self):
         # assure ports are allocated
-        for key, _ in Httpd.PORT_SPECS.items():
+        for key in Httpd.PORT_SPECS:
             assert self.ports[key] is not None
         if self._maybe_running:
             self.stop()
@@ -479,14 +479,13 @@ class Httpd:
 
             fd.write("\n".join(conf))
         with open(os.path.join(self._conf_dir, 'mime.types'), 'w') as fd:
-            fd.write("\n".join([
-                'text/plain            txt',
-                'text/html             html',
-                'application/json      json',
-                'application/x-gzip    gzip',
-                'application/x-gzip    gz',
-                ''
-            ]))
+            fd.write(textwrap.dedent("""\
+                text/plain            txt
+                text/html             html
+                application/json      json
+                application/x-gzip    gzip
+                application/x-gzip    gz
+            """))
 
     def _get_proxy_conf(self):
         if self._proxy_auth_basic:
diff --git a/tests/http/testenv/nghttpx.py b/tests/http/testenv/nghttpx.py
index 3caa99dcca..50dd5e2152 100644
--- a/tests/http/testenv/nghttpx.py
+++ b/tests/http/testenv/nghttpx.py
@@ -27,6 +27,7 @@ import os
 import signal
 import socket
 import subprocess
+import textwrap
 import time
 from datetime import datetime, timedelta
 from typing import Dict, Optional
@@ -203,10 +204,10 @@ class Nghttpx:
 
     def _write_config(self):
         with open(self._conf_file, 'w') as fd:
-            fd.write('# nghttpx test config')
-            fd.write("\n".join([
-                '# do we need something here?'
-            ]))
+            fd.write(textwrap.dedent("""\
+                # nghttpx test config
+                # do we need something here?
+            """))
 
 
 class NghttpxQuic(Nghttpx):
diff --git a/tests/negtelnetserver.py b/tests/negtelnetserver.py
index 4e65b62ec4..ad7cb53e98 100755
--- a/tests/negtelnetserver.py
+++ b/tests/negtelnetserver.py
@@ -310,9 +310,7 @@ def setup_logging(options):
     root_logger = logging.getLogger()
     add_stdout = False
 
-    formatter = logging.Formatter("%(asctime)s %(levelname)-5.5s "
-                                  "[{ident}] %(message)s"
-                                  .format(ident=IDENT))
+    formatter = logging.Formatter(f"%(asctime)s %(levelname)-5.5s [{IDENT}] %(message)s")
 
     # Write out to a logfile
     if options.logfile:
diff --git a/tests/smbserver.py b/tests/smbserver.py
index 67ca6b2962..1072fd239d 100755
--- a/tests/smbserver.py
+++ b/tests/smbserver.py
@@ -64,7 +64,7 @@ class ShutdownHandler(threading.Thread):
     """
 
     def __init__(self, server):
-        super(ShutdownHandler, self).__init__()
+        super().__init__()
         self.server = server
         self.shutdown_event = threading.Event()
 
@@ -351,7 +351,7 @@ class TestSmbServer(imp_smbserver.SMBSERVER):
 
 class SmbError(Exception):
     def __init__(self, error_code, error_message):
-        super(SmbError, self).__init__(error_message)
+        super().__init__(error_message)
         self.error_code = error_code
 
 
diff --git a/tests/util.py b/tests/util.py
index bc94f41f7e..7c0ad4b499 100755
--- a/tests/util.py
+++ b/tests/util.py
@@ -33,18 +33,18 @@ REPLY_DATA = re.compile("<reply>[ \t\n\r]*<data[^<]*>(.*?)</data>", re.MULTILINE
 
 class ClosingFileHandler(logging.StreamHandler):
     def __init__(self, filename):
-        super(ClosingFileHandler, self).__init__()
+        super().__init__()
         self.filename = os.path.abspath(filename)
         self.setStream(None)
 
     def emit(self, record):
         with open(self.filename, "a") as fp:
             self.setStream(fp)
-            super(ClosingFileHandler, self).emit(record)
+            super().emit(record)
             self.setStream(None)
 
     def setStream(self, stream):
-        setStream = getattr(super(ClosingFileHandler, self), 'setStream', None)
+        setStream = getattr(super(), 'setStream', None)
         if callable(setStream):
             return setStream(stream)
         if stream is self.stream:
@@ -66,8 +66,7 @@ class TestData:
 
     def get_test_data(self, test_number):
         # Create the test filename
-        filename = os.path.join(self.data_folder,
-                                "test{0}".format(test_number))
+        filename = os.path.join(self.data_folder, f"test{test_number}")
 
         log.debug("Parsing file %s", filename)