diff --git a/mitmproxy/tools/main.py b/mitmproxy/tools/main.py
index 568c51770..84dab1fe4 100644
--- a/mitmproxy/tools/main.py
+++ b/mitmproxy/tools/main.py
@@ -1,6 +1,8 @@
 from __future__ import print_function  # this is here for the version check to work on Python 2.
 import sys
 
+# This must be at the very top, before importing anything else that might break!
+# Keep all other imports below with the 'noqa' magic comment.
 if sys.version_info < (3, 5):
     print("#" * 49, file=sys.stderr)
     print("# mitmproxy only supports Python 3.5 and above! #", file=sys.stderr)
@@ -13,7 +15,7 @@ from mitmproxy.tools import cmdline  # noqa
 from mitmproxy import exceptions  # noqa
 from mitmproxy import options  # noqa
 from mitmproxy import optmanager  # noqa
-from mitmproxy import proxy
+from mitmproxy import proxy  # noqa
 from mitmproxy.utils import version_check  # noqa
 from mitmproxy.utils import debug  # noqa
 
diff --git a/test/conftest.py b/test/conftest.py
index 50b381971..bb9135488 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -1,8 +1,6 @@
 import os
 import pytest
 import OpenSSL
-import functools
-from contextlib import contextmanager
 
 import mitmproxy.net.tcp
 
diff --git a/test/mitmproxy/test_connections.py b/test/mitmproxy/test_connections.py
index daf4c79ec..99367bb65 100644
--- a/test/mitmproxy/test_connections.py
+++ b/test/mitmproxy/test_connections.py
@@ -1,5 +1,4 @@
 import socket
-import os
 import threading
 import ssl
 import OpenSSL