chore: apply noxfile changes for flake8 import order [(#3752)](GoogleCloudPlatform/python-docs-samples#3752)

Author: Takashi Matsuo

samples/snippets/PubSubToGCS.py

@@ -19,8 +19,8 @@
 import logging
 
 import apache_beam as beam
-import apache_beam.transforms.window as window
 from apache_beam.options.pipeline_options import PipelineOptions
+import apache_beam.transforms.window as window
 
 
 class GroupWindowsIntoBatches(beam.PTransform):

samples/snippets/PubSubToGCS_test.py

@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
 import os
 import uuid
 
@@ -21,6 +20,7 @@
 from apache_beam.testing.test_stream import TestStream
 from apache_beam.testing.test_utils import TempDir
 from apache_beam.transforms.window import TimestampedValue
+import mock
 
 import PubSubToGCS
 

samples/snippets/noxfile.py

@@ -34,10 +34,6 @@
 #
 
 
-# Ignore I202 "Additional newline in a section of imports." to accommodate
-# region tags in import blocks. Since we specify an explicit ignore, we also
-# have to explicitly ignore the list of default ignores:
-# `E121,E123,E126,E226,E24,E704,W503,W504` as shown by `flake8 --help`.
 def _determine_local_import_names(start_dir):
     """Determines all import names that should be considered "local".
 
@@ -54,13 +50,23 @@ def _determine_local_import_names(start_dir):
     ]
 
 
+# Linting with flake8.
+#
+# We ignore the following rules:
+#   E203: whitespace before ‘:’
+#   E266: too many leading ‘#’ for block comment
+#   E501: line too long
+#   I202: Additional newline in a section of imports
+#
+# We also need to specify the rules which are ignored by default:
+# ['E226', 'W504', 'E126', 'E123', 'W503', 'E24', 'E704', 'E121']
 FLAKE8_COMMON_ARGS = [
     "--show-source",
     "--builtin=gettext",
     "--max-complexity=20",
     "--import-order-style=google",
     "--exclude=.nox,.cache,env,lib,generated_pb2,*_pb2.py,*_pb2_grpc.py",
-    "--ignore=E121,E123,E126,E203,E226,E24,E266,E501,E704,W503,W504,I100,I201,I202",
+    "--ignore=E121,E123,E126,E203,E226,E24,E266,E501,E704,W503,W504,I202",
     "--max-line-length=88",
 ]
 
@@ -142,11 +148,12 @@ def _get_repo_root():
 def readmegen(session, path):
     """(Re-)generates the readme for a sample."""
     session.install("jinja2", "pyyaml")
+    dir_ = os.path.dirname(path)
 
-    if os.path.exists(os.path.join(path, "requirements.txt")):
-        session.install("-r", os.path.join(path, "requirements.txt"))
+    if os.path.exists(os.path.join(dir_, "requirements.txt")):
+        session.install("-r", os.path.join(dir_, "requirements.txt"))
 
-    in_file = os.path.join(path, "README.rst.in")
+    in_file = os.path.join(dir_, "README.rst.in")
     session.run(
         "python", _get_repo_root() + "/scripts/readme-gen/readme_gen.py", in_file
     )