Issue pypa#7280 - Clean-up python2.7, isort, and flake8 errors

tests/lib/filesystem.py

@@ -1,7 +1,7 @@
 """Helpers for filesystem-dependent tests.
 """
-import os
 import multiprocessing
+import os
 import socket
 import subprocess
 import sys
@@ -47,7 +47,8 @@ def lock_action(f):
 def external_file_opener(conn):
     """
     This external process is run with multiprocessing.
-    It waits for a path from the parent, opens it, and then wait for another message before closing it.
+    It waits for a path from the parent, opens it, and then wait for another
+     message before closing it.
 
     :param conn: bi-directional pipe
     :return: nothing
@@ -69,7 +70,7 @@ def external_file_opener(conn):
                     lock_action(f)
                 elif action == 'noread':
                     make_unreadable_file(path)
-            except OSError as e:
+            except OSError:
                 traceback.print_exc(None, sys.stderr)
 
             # Indicate the file is opened
@@ -84,23 +85,26 @@ def external_file_opener(conn):
 
 class FileOpener(object):
     """
-    Test class acts as a context manager which can open a file from another process, and hold it open
-    to assure that this does not interfere with pip's operations.
+    Test class acts as a context manager which can open a file from a
+    subprocess, and hold it open to assure that this does not interfere with
+    pip's operations.
 
-    If a path is passed to the FileOpener, it immediately sends a message to the other process to
-    open that path.  An action of "lock" or "noread" can also be sent to the subprocess, resulting
-    in various additional monkey wrenches now and in the future.
+    If a path is passed to the FileOpener, it immediately sends a message to
+    the other process to open that path.  An action of "lock" or "noread" can
+    also be sent to the subprocess, resulting in various additional monkey
+    wrenches now and in the future.
 
-    Opening the path and taking the action can be deferred however, so that the FileOpener may
-    function as a pytest fixture if so desired.
+    Opening the path and taking the action can be deferred however, so that
+    the FileOpener may function as a pytest fixture if so desired.
     """
-    def __init__(self,
-                 path=None, # type: Optional(str)
-                 action=None,  # type: Optional(str)
-                 ):
+    def __init__(self, path=None, action=None):
         self.path = None
         self.conn, child_conn = multiprocessing.Pipe()
-        self.child = multiprocessing.Process(target=external_file_opener, daemon=True, args=(child_conn,))
+        self.child = multiprocessing.Process(
+            target=external_file_opener,
+            args=(child_conn,)
+        )
+        self.child.daemon = True
         self.child.start()
         if path:
             self.send(path, action)
@@ -109,11 +113,11 @@ def send(self, path, action=None):
         if self.path is not None:
             raise AttributeError('path may only be set once')
         self.path = str(path)
-        self.conn.send( (str(path), action) )
+        self.conn.send((str(path), action))
         return self.conn.recv()
 
     def cleanup(self):
-        # send a message to the child to exit; it will exit whether the path was sent or not
+        # send a message to the child to exit
         if self.child:
             self.conn.send(True)
             self.child.join()

tests/unit/test_utils_filesystem.py

@@ -5,7 +5,11 @@
 import pytest
 
 from pip._internal.utils.filesystem import copy2_fixed, is_socket
-from tests.lib.filesystem import make_socket_file, make_unreadable_file, FileOpener
+from tests.lib.filesystem import (
+    FileOpener,
+    make_socket_file,
+    make_unreadable_file,
+)
 from tests.lib.path import Path
 
 
@@ -69,36 +73,39 @@ def test_copy2_fixed_raises_appropriate_errors(create, error_type, tmpdir):
 
 
 def test_file_opener_no_file(process):
-    # The FileOpener cleans up the subprocess even if the parent never sends the path
+    # FileOpener joins the subprocess even if the parent never sends the path
     with FileOpener():
         pass
     assert len(process.children()) == 0
 
 
 def test_file_opener_not_found(tmpdir, process):
-    # The FileOpener cleans up the subprocess even if the file cannot be opened
+    # The FileOpener cleans up the subprocess when the file cannot be opened
     path = tmpdir.joinpath('foo.txt')
     with FileOpener(path):
         pass
     assert len(process.children()) == 0
 
 
 def test_file_opener_normal(tmpdir, process):
-    # The FileOpener cleans up the subprocess when the file exists; also tests that path may be deferred
+    # The FileOpener cleans up the subprocess when the file exists
     path = tmpdir.joinpath('foo.txt')
     with open(path, 'w') as f:
         f.write('Hello\n')
-    with FileOpener() as opener:
-        opener.send(path)
+    with FileOpener(path):
+        pass
     assert len(process.children()) == 0
 
 
 @skip_unless_windows
 def test_file_opener_produces_unlink_error(tmpdir, process):
+    # FileOpener forces an error on Windows when we attempt to remove a file
+    # The initial path may be deferred; which must be tested with an error
     path = tmpdir.joinpath('foo.txt')
     with open(path, 'w') as f:
         f.write('Hello\n')
-    with FileOpener(path):
+    with FileOpener() as opener:
+        opener.send(path)
         with pytest.raises(OSError):
             os.unlink(path)
 

tests/unit/test_utils_temp_dir.py

@@ -15,7 +15,6 @@
     TempDirectory,
     global_tempdir_manager,
 )
-
 from tests.lib.filesystem import FileOpener
 
 
@@ -223,7 +222,7 @@ def test_temp_dir_warns_if_cannot_clean(caplog):
 
     # Capture only at WARNING level and up
     with caplog.at_level(logging.WARNING, 'pip._internal.utils.temp_dir'):
-        # open a file within the temporary directory in a sub-process, so it cannot be cleaned up
+        # open a file within the temporary directory in a sub-process
         with FileOpener() as opener:
             subpath = os.path.join(temp_dir_path, 'foo.txt')
             with open(subpath, 'w') as f:
@@ -232,11 +231,11 @@ def test_temp_dir_warns_if_cannot_clean(caplog):
             # with the file open, attempt to remove the log directory
             temp_dir.cleanup()
 
-        # assert that a WARNING was logged and that it contains a note about a potential virus scanner
+        # assert that a WARNING was logged about virus scanner
         assert 'WARNING' in caplog.text
         assert 'virus scanner' in caplog.text
 
-    # Assure that the cleanup was properly retried; this fix did not change retries
+    # Assure that the cleanup was properly retried
     duration = time.time() - stime
     assert duration >= 2.0