style: apply black via pre-commit run -a

test/test_pure_wheel.py

@@ -6,7 +6,9 @@ import pytest
 from . import utils
 
 pure_python_project = test_projects.TestProject()
-pure_python_project.files['setup.py'] = '''
+pure_python_project.files[
+    'setup.py'
+] = '''
 from setuptools import Extension, setup
 
 setup(
@@ -16,7 +18,9 @@ setup(
 )
 '''
 
-pure_python_project.files['spam.py'] = '''
+pure_python_project.files[
+    'spam.py'
+] = '''
 def a_function():
     pass
 '''