Major error.py refactoring to match flake8 guidelines

Changes:
1. Fixes missing parents with `pip` installation, closes #30
2. Now respects `noqa` comments, closes #10

pyproject.toml

@@ -37,7 +37,7 @@ classifiers = [
 ]
 
 [tool.poetry.plugins."flake8.extension"]
-WPS = "wemake_python_styleguide.checker:Checker"
+Z = "wemake_python_styleguide.checker:Checker"
 
 [tool.poetry.dependencies]
 python = "^3.6"
@@ -51,7 +51,6 @@ pytest = "^3.6"
 flake8-builtins = "^1.4"
 flake8-commas = "^2.0"
 flake8-quotes = "^1.0"
-flake8-pep3101 = "^1.2"
 flake8-comprehensions = "^1.4"
 flake8-blind-except = "^0.1.1"
 flake8-docstrings = "^1.3"

tests/conftest.py

@@ -1,9 +1,29 @@
 # -*- coding: utf-8 -*-
 
+import inspect
 import os
+from operator import itemgetter
 
 import pytest
 
+from wemake_python_styleguide import errors
+
+
+def _is_error_class(cls) -> bool:
+    return (
+        inspect.isclass(cls) and
+        issubclass(cls, errors.BaseStyleViolation) and
+        cls is not errors.BaseStyleViolation
+    )
+
+
+@pytest.fixture(scope='module')
+def all_errors():
+    """Loads all errors from the package."""
+    return list(
+        map(itemgetter(1), inspect.getmembers(errors, _is_error_class)),
+    )
+
 
 @pytest.fixture(scope='session')
 def absolute_path():

tests/fixtures/noqa.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+
+"""
+This file contains all possible errors.
+"""
+
+from .version import get_version  # noqa: Z100
+def some():
+    from my_module import some_function  # noqa: Z101
+
+
+del {'a': 1}['a'] # noqa: Z102
+raise  # noqa: Z103
+raise NotImplemented  # noqa: Z104
+hasattr(object, 'some')  # noqa: Z105
+value = 1  # noqa: Z106
+x = 2  # noqa: Z107
+__private = 3  # noqa: Z108
+__author__ = 'Nikita Sobolev'  # noqa: Z109
+

tests/test_options/test_config.py → tests/test_checkers/test_config.py

@@ -14,7 +14,7 @@ def test_max_variables_cli_option(absolute_path):
         stderr=subprocess.PIPE,
     )
     stdout, _ = process.communicate()
-    assert stdout.count(b'WPS150') == 0
+    assert stdout.count(b'Z150') == 0
 
 
 def test_max_arguments_cli_option(absolute_path):
@@ -28,7 +28,7 @@ def test_max_arguments_cli_option(absolute_path):
         stderr=subprocess.PIPE,
     )
     stdout, _ = process.communicate()
-    assert stdout.count(b'WPS151') == 0
+    assert stdout.count(b'Z151') == 0
 
 
 def test_max_returns_cli_option(absolute_path):
@@ -42,7 +42,7 @@ def test_max_returns_cli_option(absolute_path):
         stderr=subprocess.PIPE,
     )
     stdout, _ = process.communicate()
-    assert stdout.count(b'WPS153') == 0
+    assert stdout.count(b'Z153') == 0
 
 
 def test_max_expressions_cli_options(absolute_path):
@@ -56,4 +56,4 @@ def test_max_expressions_cli_options(absolute_path):
         stderr=subprocess.PIPE,
     )
     stdout, _ = process.communicate()
-    assert stdout.count(b'WPS154') == 0
+    assert stdout.count(b'Z154') == 0

tests/test_checkers/test_high_complexity.py

@@ -7,49 +7,49 @@ def test_too_many_variables_in_fixture(absolute_path):
     """End-to-End test to check variables count."""
     filename = absolute_path('fixtures', 'complexity', 'wrong_variables.py')
     process = subprocess.Popen(
-        ['flake8', filename],
+        ['flake8', '--select', 'Z', filename],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
     )
     stdout, _ = process.communicate()
 
-    assert stdout.count(b'WPS150') == 2
+    assert stdout.count(b'Z202') == 2
 
 
 def test_too_many_arguments_in_fixture(absolute_path):
     """End-to-End test to check arguments count."""
     filename = absolute_path('fixtures', 'complexity', 'wrong_arguments.py')
     process = subprocess.Popen(
-        ['flake8', filename],
+        ['flake8', '--select', 'Z', filename],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
     )
     stdout, _ = process.communicate()
 
-    assert stdout.count(b'WPS151') == 4
+    assert stdout.count(b'Z203') == 4
 
 
 def test_too_many_returns_in_fixture(absolute_path):
     """End-to-End test to check returns count."""
     filename = absolute_path('fixtures', 'complexity', 'wrong_returns.py')
     process = subprocess.Popen(
-        ['flake8', filename],
+        ['flake8', '--select', 'Z', filename],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
     )
     stdout, _ = process.communicate()
 
-    assert stdout.count(b'WPS153') == 1
+    assert stdout.count(b'Z205') == 1
 
 
 def test_too_many_expressions_in_fixture(absolute_path):
     """End-to-End test to check expressions count."""
     filename = absolute_path('fixtures', 'complexity', 'wrong_expressions.py')
     process = subprocess.Popen(
-        ['flake8', filename],
+        ['flake8', '--select', 'Z', filename],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
     )
     stdout, _ = process.communicate()
 
-    assert stdout.count(b'WPS154') == 1
+    assert stdout.count(b'Z206') == 1

tests/test_checkers/test_noqa.py

@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+
+import subprocess
+
+
+def test_noqa_fixture_disabled(absolute_path):
+    """End-to-End test to check that all errors are present."""
+    filename = absolute_path('fixtures', 'noqa.py')
+    process = subprocess.Popen(
+        ['flake8', '--disable-noqa', '--select', 'Z', filename],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+    )
+    stdout, _ = process.communicate()
+
+    assert stdout.count(b'Z') > 0
+
+
+def test_noqa_fixture(absolute_path):
+    """End-to-End test to check that `noqa` works."""
+    filename = absolute_path('fixtures', 'noqa.py')
+    process = subprocess.Popen(
+        ['flake8', '--select', 'Z', filename],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+    )
+    stdout, _ = process.communicate()
+
+    assert stdout.count(b'Z') == 0

tests/test_checkers/test_wrong_variable.py

@@ -7,13 +7,13 @@ def test_wrong_variables_in_fixture(absolute_path):
     """End-to-End test to check variable rules."""
     filename = absolute_path('fixtures', 'wrong_variable.py')
     process = subprocess.Popen(
-        ['flake8', filename],
+        ['flake8', '--select', 'Z', filename],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
     )
     stdout, _ = process.communicate()
 
-    assert stdout.count(b'WPS120') == 12
-    assert stdout.count(b'WPS121') == 6
-    assert stdout.count(b'WPS122') == 1
-    assert stdout.count(b'WPS123') == 1
+    assert stdout.count(b'Z106') == 12
+    assert stdout.count(b'Z107') == 6
+    assert stdout.count(b'Z108') == 1
+    assert stdout.count(b'Z109') == 1

tests/test_errors.py

@@ -1,28 +1,5 @@
 # -*- coding: utf-8 -*-
 
-import inspect
-from operator import itemgetter
-
-import pytest
-
-from wemake_python_styleguide import errors
-
-
-def _is_error_class(cls) -> bool:
-    return (
-        inspect.isclass(cls) and
-        issubclass(cls, errors.BaseStyleViolation) and
-        cls is not errors.BaseStyleViolation
-    )
-
-
-@pytest.fixture(scope='module')
-def all_errors():
-    """Loads all errors from the package."""
-    return list(
-        map(itemgetter(1), inspect.getmembers(errors, _is_error_class)),
-    )
-
 
 def test_all_unique_error_codes(all_errors):
     """Ensures that all errors have unique error codes."""

tests/test_visitors/conftest.py

@@ -6,20 +6,15 @@
 
 import pytest
 
+from wemake_python_styleguide.compat import maybe_set_parent
 from wemake_python_styleguide.visitors.base.visitor import BaseNodeVisitor
 
 
 @pytest.fixture(scope='session')
 def parse_ast_tree():
     """Helper function to convert code to ast."""
     def factory(code: str) -> ast.AST:
-        tree = ast.parse(dedent(code))
-
-        for statement in ast.walk(tree):
-            for child in ast.iter_child_nodes(statement):
-                child.parent = statement
-
-        return tree
+        return maybe_set_parent(ast.parse(dedent(code)))
 
     return factory
 

wemake_python_styleguide/checker.py

@@ -3,6 +3,7 @@
 from ast import Module
 from typing import Generator, Tuple
 
+from wemake_python_styleguide.compat import maybe_set_parent
 from wemake_python_styleguide.options.config import Configuration
 from wemake_python_styleguide.version import version
 from wemake_python_styleguide.visitors.high_complexity import ComplexityVisitor
@@ -38,7 +39,7 @@ class Checker(object):
 
     def __init__(self, tree: Module, filename: str = '-') -> None:
         """Creates new checker instance."""
-        self.tree = tree
+        self.tree = maybe_set_parent(tree)
         self.filename = filename
 
         self._visitors = (

wemake_python_styleguide/compat.py

@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+
+"""
+This module contains ugly hacks and fixes for version compat issues.
+
+Do not be over-exited to add anything here.
+"""
+
+import ast
+
+
+def maybe_set_parent(tree: ast.AST) -> ast.AST:
+    """Sets parents for all nodes that do not have this prop."""
+    for statement in ast.walk(tree):
+        for child in ast.iter_child_nodes(statement):
+            if not hasattr(child, 'parent'):  # noqa: Z105
+                setattr(child, 'parent', statement)  # noqa: Z105
+
+    return tree

wemake_python_styleguide/constants.py

@@ -30,6 +30,9 @@
 
     # Misc:
     'copyright',
+
+    # Dynamic imports:
+    '__import__',
 ))
 
 #: List of module metadata we forbid to use.