Issue #1191: Forbid to use unreadable characters

CHANGELOG.md

@@ -47,6 +47,8 @@ Semantic versioning in our case means:
 - Adds baseline information for all complexity violation messages: `x > baseline`
 - Changes how cognitive complexity is calculated
 - Adds support for positional arguments in different checks
+- Adds `UnreadableNameViolation` as `WPS124` because there are some
+character combination which is not easy to read
 - Adds support for `NamedExpr` with in compare type violation
 
 ### Bugfixes

tests/fixtures/noqa/noqa.py

@@ -703,3 +703,9 @@ def consecutive_yields():
         # https://github.com/wemake-services/wemake-python-styleguide/issues/1082
         break
     my_print(4)
+
+
+class Mem0Output(object):  # noqa: WPS124
+    # See:
+    # https://github.com/wemake-services/wemake-python-styleguide/issues/1191
+    anti_wps124 = 'unreadable class'

tests/test_checker/test_noqa.py

@@ -71,6 +71,7 @@
     'WPS121': 1,
     'WPS122': 1,
     'WPS123': 1,
+    'WPS124': 1,
 
     'WPS200': 0,  # logically unacceptable.
     'WPS201': 0,  # defined in ignored violations.

tests/test_formatter/snapshots/snap_test_formatter_output.py

@@ -12,7 +12,7 @@
 snapshots['test_formatter[cli_options2-with_source] formatter_with_source'] = '''
 \x1b[4m\x1b[1m./tests/fixtures/formatter/formatter1.py\x1b[0m\x1b[0m
 
-  1:1      WPS111 Found too short name: s
+  1:1      WPS111 Found too short name: s < 2
   \x1b[34mdef\x1b[39;49;00m \x1b[32ms\x1b[39;49;00m(handle: \x1b[36mint\x1b[39;49;00m) -> \x1b[36mint\x1b[39;49;00m:
   ^
 
@@ -68,7 +68,7 @@
 snapshots['test_formatter[cli_options3-with_source_statistic] formatter_with_source_statistic'] = '''
 \x1b[4m\x1b[1m./tests/fixtures/formatter/formatter1.py\x1b[0m\x1b[0m
 
-  1:1      WPS111 Found too short name: s
+  1:1      WPS111 Found too short name: s < 2
   \x1b[34mdef\x1b[39;49;00m \x1b[32ms\x1b[39;49;00m(handle: \x1b[36mint\x1b[39;49;00m) -> \x1b[36mint\x1b[39;49;00m:
   ^
 
@@ -107,7 +107,7 @@
   2     ./tests/fixtures/formatter/formatter2.py
 \x1b[4mTotal: 3\x1b[0m
 
-\x1b[1mWPS111\x1b[0m: Found too short name: s
+\x1b[1mWPS111\x1b[0m: Found too short name: s < 2
   1     ./tests/fixtures/formatter/formatter1.py
 \x1b[4mTotal: 1\x1b[0m
 
@@ -134,7 +134,7 @@
 snapshots['test_formatter[cli_options4-statistic_with_source] formatter_statistic_with_source'] = '''
 \x1b[4m\x1b[1m./tests/fixtures/formatter/formatter1.py\x1b[0m\x1b[0m
 
-  1:1      WPS111 Found too short name: s
+  1:1      WPS111 Found too short name: s < 2
   \x1b[34mdef\x1b[39;49;00m \x1b[32ms\x1b[39;49;00m(handle: \x1b[36mint\x1b[39;49;00m) -> \x1b[36mint\x1b[39;49;00m:
   ^
 
@@ -173,7 +173,7 @@
   2     ./tests/fixtures/formatter/formatter2.py
 \x1b[4mTotal: 3\x1b[0m
 
-\x1b[1mWPS111\x1b[0m: Found too short name: s
+\x1b[1mWPS111\x1b[0m: Found too short name: s < 2
   1     ./tests/fixtures/formatter/formatter1.py
 \x1b[4mTotal: 1\x1b[0m
 
@@ -199,7 +199,7 @@
 
 snapshots['test_formatter[cli_options0-regular] formatter_regular'] = '''
 \x1b[4m\x1b[1m./tests/fixtures/formatter/formatter1.py\x1b[0m\x1b[0m
-  1:1      WPS111 Found too short name: s
+  1:1      WPS111 Found too short name: s < 2
   1:7      WPS110 Found wrong variable name: handle
   2:21     WPS432 Found magic number: 200
   2:21     WPS303 Found underscored number: 2_00
@@ -216,7 +216,7 @@
 
 snapshots['test_formatter[cli_options1-regular_statistic] formatter_regular_statistic'] = '''
 \x1b[4m\x1b[1m./tests/fixtures/formatter/formatter1.py\x1b[0m\x1b[0m
-  1:1      WPS111 Found too short name: s
+  1:1      WPS111 Found too short name: s < 2
   1:7      WPS110 Found wrong variable name: handle
   2:21     WPS432 Found magic number: 200
   2:21     WPS303 Found underscored number: 2_00
@@ -232,7 +232,7 @@
   2     ./tests/fixtures/formatter/formatter2.py
 \x1b[4mTotal: 3\x1b[0m
 
-\x1b[1mWPS111\x1b[0m: Found too short name: s
+\x1b[1mWPS111\x1b[0m: Found too short name: s < 2
   1     ./tests/fixtures/formatter/formatter1.py
 \x1b[4mTotal: 1\x1b[0m
 

tests/test_visitors/test_ast/test_conditions/test_useless_len_call.py

@@ -35,6 +35,7 @@ def test_useful_len_call(
 
 @pytest.mark.parametrize('code', [
     wrong_len_call1,
+    wrong_len_call2,
 ])
 def test_useless_len_call(
     assert_errors,

tests/test_visitors/test_ast/test_naming/test_naming_rules/test_long.py

@@ -18,7 +18,7 @@ def test_long_variable_name(
     visitor.run()
 
     assert_errors(visitor, [TooLongNameViolation])
-    assert_error_text(visitor, long_name)
+    assert_error_text(visitor, long_name, default_options.max_name_length)
 
 
 def test_long_variable_name_config(

tests/test_visitors/test_ast/test_naming/test_naming_rules/test_redability.py

@@ -0,0 +1,46 @@
+import pytest
+
+from wemake_python_styleguide import constants
+from wemake_python_styleguide.logic.naming.alphabet import (
+    get_unreadable_characters,
+)
+from wemake_python_styleguide.violations.naming import UnreadableNameViolation
+from wemake_python_styleguide.visitors.ast.naming import WrongNameVisitor
+
+class_template = """
+class {0}(object):
+    def __init__(self):
+        ...
+"""
+
+
+@pytest.mark.parametrize('code', [
+    class_template,
+])
+@pytest.mark.parametrize('expression', [
+    'My1Item',
+    'Element0Operation',
+    'O0S',
+    'S0O',
+])
+def test_unreadable_name(
+    assert_errors,
+    assert_error_text,
+    parse_ast_tree,
+    code,
+    expression,
+    default_options,
+    mode,
+):
+    """Ensures that unreadable names are not allowed."""
+    tree = parse_ast_tree(mode(code.format(expression, expression)))
+
+    visitor = WrongNameVisitor(default_options, tree=tree)
+    visitor.run()
+
+    unreadable = get_unreadable_characters(
+        expression, constants.UNREADABLE_CHARACTER_COMBINATIONS,
+    )
+
+    assert_errors(visitor, [UnreadableNameViolation])
+    assert_error_text(visitor, unreadable)

tests/test_visitors/test_ast/test_naming/test_naming_rules/test_short.py

@@ -27,7 +27,7 @@ def test_short_variable_name(
     visitor.run()
 
     assert_errors(visitor, [TooShortNameViolation])
-    assert_error_text(visitor, short_name)
+    assert_error_text(visitor, short_name, default_options.min_name_length)
 
 
 @pytest.mark.parametrize('short_name', [
@@ -70,4 +70,4 @@ def test_naming_length_settings(
     visitor.run()
 
     assert_errors(visitor, [TooShortNameViolation])
-    assert_error_text(visitor, short_name)
+    assert_error_text(visitor, short_name, option_values.min_name_length)

tests/test_visitors/test_filenames/test_module/test_module_name_length.py

@@ -47,7 +47,9 @@ def test_length_option(assert_errors, assert_error_text, options):
     visitor.run()
 
     assert_errors(visitor, [TooShortNameViolation])
-    assert_error_text(visitor, filename.replace('.py', ''))
+    assert_error_text(
+        visitor, filename.replace('.py', ''), option_values.min_name_length,
+    )
 
 
 @pytest.mark.parametrize('filename', [
@@ -73,4 +75,6 @@ def test_max_length_option(assert_errors, assert_error_text, options):
     visitor.run()
 
     assert_errors(visitor, [TooLongNameViolation])
-    assert_error_text(visitor, filename.replace('.py', ''))
+    assert_error_text(
+        visitor, filename.replace('.py', ''), option_values.max_name_length,
+    )

tests/test_visitors/test_filenames/test_module/test_module_redable_name.py

@@ -0,0 +1,47 @@
+import pytest
+
+from wemake_python_styleguide.violations.naming import (
+    UnderscoredNumberNameViolation,
+    UnreadableNameViolation,
+    WrongModuleNamePatternViolation,
+)
+from wemake_python_styleguide.visitors.filenames.module import (
+    WrongModuleNameVisitor,
+)
+
+
+@pytest.mark.parametrize('filename', [
+    'the1long',
+])
+def test_unreadable_filename(assert_errors, filename, default_options):
+    """Testing that unreadable characters combinations do not allowed."""
+    visitor = WrongModuleNameVisitor(default_options, filename=filename)
+    visitor.run()
+
+    assert_errors(visitor, [UnreadableNameViolation])
+
+
+@pytest.mark.parametrize('filename', [
+    'ordinary',
+    'first_module',
+])
+def test_readable_filename(assert_errors, filename, default_options):
+    """Testing that ordinary naming works well."""
+    visitor = WrongModuleNameVisitor(default_options, filename=filename)
+    visitor.run()
+
+    assert_errors(visitor, [])
+
+
+@pytest.mark.parametrize('filename', [
+    'TestO_0',
+])
+def test_corner_case(assert_errors, filename, default_options):
+    """Testing corner case related to underscore name patterns."""
+    visitor = WrongModuleNameVisitor(default_options, filename=filename)
+    visitor.run()
+
+    assert_errors(visitor, [
+        WrongModuleNamePatternViolation,
+        UnderscoredNumberNameViolation,
+    ])

wemake_python_styleguide/constants.py

@@ -107,6 +107,16 @@
     'baz',
 ))
 
+#: List of characters sequences that are hard to read.
+UNREADABLE_CHARACTER_COMBINATIONS: Final = frozenset((
+    '1l',
+    '1I',
+    '0O',
+    'O0',
+    # Not included: 'lI', 'l1', 'Il'
+    # Because these names are quite common in real words.
+))
+
 #: List of special names that are used only as first argument in methods.
 SPECIAL_ARGUMENT_NAMES_WHITELIST: Final = frozenset((
     'self',
@@ -366,11 +376,17 @@
 ))
 
 #: List of functions in which arguments must be tuples.
-TUPLE_ARGUMENTS_METHODS = frozenset((
+TUPLE_ARGUMENTS_METHODS: Final = frozenset((
     'frozenset',
 ))
 
+
 # Internal variables
+# ==================
+
+# Please, do not touch values beyond this line!
+# ---------------------------------------------
+
 # They are not publicly documented since they are not used by the end user.
 # But, we still need them to be defined here.