Rename main_util_fixtures.py to conftest.py to allow fixture auto discovery

Also fix new PEP-008 issues.

test/10_cpp_standards/cibuildwheel_test.py

@@ -1,13 +1,12 @@
 import os
-import sys 
 
 import pytest
 
 import utils
 
-
 project_dir = os.path.dirname(__file__)
 
+
 def test_cpp11(tmp_path):
     # This test checks that the C++11 standard is supported
 
@@ -18,8 +17,8 @@ def test_cpp11(tmp_path):
 
     actual_wheels = utils.cibuildwheel_run(project_dir, add_env=add_env)
     expected_wheels = [x for x in utils.expected_wheels(
-                            'spam', '0.1.0', macosx_deployment_target='10.9')
-                       if 'cp27-cp27m-win' not in x]
+        'spam', '0.1.0', macosx_deployment_target='10.9')
+        if 'cp27-cp27m-win' not in x]
     assert set(actual_wheels) == set(expected_wheels)
 
 
@@ -35,15 +34,15 @@ def test_cpp14():
 
     actual_wheels = utils.cibuildwheel_run(project_dir, add_env=add_env)
     expected_wheels = [x for x in utils.expected_wheels(
-                            'spam', '0.1.0', macosx_deployment_target='10.9')
-                       if 'cp27-cp27m-win' not in x and 'cp35-cp35m-win' not in x]
+        'spam', '0.1.0', macosx_deployment_target='10.9')
+        if 'cp27-cp27m-win' not in x and 'cp35-cp35m-win' not in x]
     assert set(actual_wheels) == set(expected_wheels)
 
 
 def test_cpp17():
     # This test checks that the C++17 standard is supported
 
-    # Python 2.7 uses the `register` keyword which is forbidden in the C++17 standard 
+    # Python 2.7 uses the `register` keyword which is forbidden in the C++17 standard
     # The manylinux1 docker image does not have a compiler which supports C++11
     # Python 3.4 and 3.5 are compiled with MSVC 10, which does not support C++17
     if os.environ.get('APPVEYOR_BUILD_WORKER_IMAGE', '') == 'Visual Studio 2015':
@@ -55,6 +54,6 @@ def test_cpp17():
 
     actual_wheels = utils.cibuildwheel_run(project_dir, add_env=add_env)
     expected_wheels = [x for x in utils.expected_wheels(
-                            'spam', '0.1.0', macosx_deployment_target='10.13')
-                       if 'cp27-cp27m-win' not in x and 'cp35-cp35m-win' not in x]
+        'spam', '0.1.0', macosx_deployment_target='10.13')
+        if 'cp27-cp27m-win' not in x and 'cp35-cp35m-win' not in x]
     assert set(actual_wheels) == set(expected_wheels)

test/10_cpp_standards/setup.py

@@ -1,7 +1,11 @@
-import os, sys
-from setuptools import setup, Extension
+import os
 import platform
 
+from setuptools import (
+    Extension,
+    setup,
+)
+
 standard = os.environ["STANDARD"]
 
 language_standard = "/std:c++" + standard if platform.system() == "Windows" else "-std=c++" + standard