diff --git a/.pylintrc b/.pylintrc
index 6df1145..78b6d2c 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -12,7 +12,8 @@ disable=
   wrong-import-position,
   redefined-outer-name,
   invalid-name,
-  no-self-use
+  no-self-use,
+  too-many-instance-attributes
 
 [FORMAT]
 indent-string='  '
diff --git a/src/bot.py b/src/bot.py
index 0692a1c..16e1320 100644
--- a/src/bot.py
+++ b/src/bot.py
@@ -91,7 +91,7 @@ class Music(commands.Cog):
 
         def after(err):
           if err:
-            self.logger.error(f"Player error: {err}")
+            self.logger.error("Player error: %s", err)
           self._next()
         ctx.voice_client.play(audio, after=after)
         embed = NowPlayingMessage(title=song.title, url=song.webpage_url)
@@ -99,7 +99,7 @@ class Music(commands.Cog):
         await self._add_skip_button(msg)
       # pylint: disable=broad-except
       except Exception as err:
-        self.logger.error(f"Error during playback: {err}")
+        self.logger.error("Error during playback: %s", err)
         if ctx:
           embed = ErrorMessage(str(err))
           await ctx.send(embed=embed)
@@ -172,7 +172,7 @@ if __name__ == "__main__":
 
   @bot.event
   async def on_ready():
-    logger.info(f"Logged in as {bot.user} ({bot.user.id})")
+    logger.info("Logged in as %s (%s)", bot.user, bot.user.id)
     logger.info('------')
 
   bot.add_cog(Music(bot, logger=logger))
diff --git a/src/log.py b/src/log.py
index f64ab58..21cb5f3 100644
--- a/src/log.py
+++ b/src/log.py
@@ -22,7 +22,7 @@ def create_logger(name: str) -> logging.Logger:
 
   COMMIT = os.getenv('GIT_COMMIT') or 'no-commit'
   timestamp = datetime.now().strftime("%Y-%m-%dT%H:%M:%S")
-  log_path = "%s_%s.log" % (COMMIT, timestamp)
+  log_path = f"{COMMIT}_{timestamp}.log"
 
   file_handler = logging.FileHandler(log_path)
 
diff --git a/test/conftest.py b/test/conftest.py
index 6da72fa..5413a8f 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -16,7 +16,7 @@ from bot import Music
 
 
 @pytest.fixture(scope="session", autouse=True)
-def start_xvfb_server(request):
+def global_teardown():
   yield
   logs = glob.glob('*.log')
   for log in logs: