fix: linter errors

src/flake8/cacher.py

@@ -1,21 +1,25 @@
-"""Cache files manager"""
+"""Cache files manager."""
 import hashlib
+import marshal
 import os
-import pickle
 
 
 class Cacher(object):
+    """Class to implement saving/loading cache for given file."""
+
     def __init__(self, file_name, cache_path):
         # type: (str, str) -> None
+        """Init cache class for the given file."""
         self.file_name = file_name
-        enc = hashlib.md5(file_name.encode())
-        self.cache_path = os.path.join(cache_path, str(enc.hexdigest()))
+        checksum = hashlib.md5(file_name.encode())  # nosec
+        self.cache_path = os.path.join(cache_path, str(checksum.hexdigest()))
 
     def get(self):
+        """Get cached result from the cache_path if available and valid."""
         if not os.path.exists(self.cache_path):
             return
         with open(self.cache_path, "rb") as fr:
-            mtime, results = pickle.load(fr)
+            mtime, results = marshal.load(fr)  # nosec
             # if the mtime doesn't change then return cache.
             # otherwise it is invalid
             current_mtime = os.path.getmtime(self.file_name)
@@ -23,7 +27,7 @@ class Cacher(object):
                 return results
 
     def save(self, results):
-        """saves the given result to the cache file"""
+        """Save the given result to the cache file."""
         with open(self.cache_path, "wb") as fw:
             current_mtime = os.path.getmtime(self.file_name)
-            pickle.dump((current_mtime, results), fw)
+            marshal.dump((current_mtime, results), fw)

src/flake8/checker.py

@@ -13,8 +13,8 @@ try:
 except ImportError:
     multiprocessing = None  # type: ignore
 
-from flake8 import defaults
 from flake8 import cacher
+from flake8 import defaults
 from flake8 import exceptions
 from flake8 import processor
 from flake8 import utils
@@ -585,7 +585,7 @@ class FileChecker(object):
             self.run_logical_checks()
 
     def run_checks(self):
-        """cached wrapper of self.run_checks"""
+        """Cache wrapper of self.run_checks."""
         # handle both cases where cache is enabled/disabled or invalid
         cache_available = False
         if self.options.cache:

tests/unit/conftest.py

@@ -12,6 +12,7 @@ def options_from(**kwargs):
     kwargs.setdefault('verbose', False)
     kwargs.setdefault('stdin_display_name', 'stdin')
     kwargs.setdefault('disable_noqa', False)
+    kwargs.setdefault('cache_location', ".cache/flake8")
     return argparse.Namespace(**kwargs)
 
 

tests/unit/test_file_checker.py

@@ -1,4 +1,6 @@
 """Unit tests for the FileChecker class."""
+import argparse
+
 import mock
 import pytest
 
@@ -6,6 +8,12 @@ import flake8
 from flake8 import checker
 
 
+def options(**kwargs):
+    """Generate argparse.Namespace for our Application."""
+    kwargs.setdefault('cache_location', ".cache/flake8")
+    return argparse.Namespace(**kwargs)
+
+
 @mock.patch('flake8.processor.FileProcessor')
 def test_run_ast_checks_handles_SyntaxErrors(FileProcessor):  # noqa: N802,N803
     """Stress our SyntaxError handling.
@@ -16,7 +24,7 @@ def test_run_ast_checks_handles_SyntaxErrors(FileProcessor):  # noqa: N802,N803
     FileProcessor.return_value = processor
     processor.build_ast.side_effect = SyntaxError('Failed to build ast',
                                                   ('', 1, 5, 'foo(\n'))
-    file_checker = checker.FileChecker(__file__, checks={}, options=object())
+    file_checker = checker.FileChecker(__file__, checks={}, options=options())
 
     with mock.patch.object(file_checker, 'report') as report:
         file_checker.run_ast_checks()
@@ -31,14 +39,14 @@ def test_run_ast_checks_handles_SyntaxErrors(FileProcessor):  # noqa: N802,N803
 def test_repr(*args):
     """Verify we generate a correct repr."""
     file_checker = checker.FileChecker(
-        'example.py', checks={}, options=object(),
+        'example.py', checks={}, options=options(),
     )
     assert repr(file_checker) == 'FileChecker for example.py'
 
 
 def test_nonexistent_file():
     """Verify that checking non-existent file results in an error."""
-    c = checker.FileChecker("foobar.py", checks={}, options=object())
+    c = checker.FileChecker("foobar.py", checks={}, options=options())
 
     assert c.processor is None
     assert not c.should_process