cpython/Lib/test/test_tabnanny.py

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"""Testing `tabnanny` module.
Glossary:
* errored : Whitespace related problems present in file.
"""
from unittest import TestCase, mock
import errno
import os
import tabnanny
import tokenize
import tempfile
import textwrap
from test.support import (captured_stderr, captured_stdout, script_helper,
findfile)
from test.support.os_helper import unlink
SOURCE_CODES = {
"incomplete_expression": (
'fruits = [\n'
' "Apple",\n'
' "Orange",\n'
' "Banana",\n'
'\n'
'print(fruits)\n'
),
"wrong_indented": (
'if True:\n'
' print("hello")\n'
' print("world")\n'
'else:\n'
' print("else called")\n'
),
"nannynag_errored": (
'if True:\n'
' \tprint("hello")\n'
'\tprint("world")\n'
'else:\n'
' print("else called")\n'
),
"error_free": (
'if True:\n'
' print("hello")\n'
' print("world")\n'
'else:\n'
' print("else called")\n'
),
"tab_space_errored_1": (
'def my_func():\n'
'\t print("hello world")\n'
'\t if True:\n'
'\t\tprint("If called")'
),
"tab_space_errored_2": (
'def my_func():\n'
'\t\tprint("Hello world")\n'
'\t\tif True:\n'
'\t print("If called")'
)
}
class TemporaryPyFile:
"""Create a temporary python source code file."""
def __init__(self, source_code='', directory=None):
self.source_code = source_code
self.dir = directory
def __enter__(self):
with tempfile.NamedTemporaryFile(
mode='w', dir=self.dir, suffix=".py", delete=False
) as f:
f.write(self.source_code)
self.file_path = f.name
return self.file_path
def __exit__(self, exc_type, exc_value, exc_traceback):
unlink(self.file_path)
class TestFormatWitnesses(TestCase):
"""Testing `tabnanny.format_witnesses()`."""
def test_format_witnesses(self):
"""Asserting formatter result by giving various input samples."""
tests = [
('Test', 'at tab sizes T, e, s, t'),
('', 'at tab size '),
('t', 'at tab size t'),
(' t ', 'at tab sizes , , t, , '),
]
for words, expected in tests:
with self.subTest(words=words, expected=expected):
self.assertEqual(tabnanny.format_witnesses(words), expected)
class TestErrPrint(TestCase):
"""Testing `tabnanny.errprint()`."""
def test_errprint(self):
"""Asserting result of `tabnanny.errprint()` by giving sample inputs."""
tests = [
(['first', 'second'], 'first second\n'),
(['first'], 'first\n'),
([1, 2, 3], '1 2 3\n'),
([], '\n')
]
for args, expected in tests:
with self.subTest(arguments=args, expected=expected):
with self.assertRaises(SystemExit):
with captured_stderr() as stderr:
tabnanny.errprint(*args)
self.assertEqual(stderr.getvalue() , expected)
class TestNannyNag(TestCase):
def test_all_methods(self):
"""Asserting behaviour of `tabnanny.NannyNag` exception."""
tests = [
(
tabnanny.NannyNag(0, "foo", "bar"),
{'lineno': 0, 'msg': 'foo', 'line': 'bar'}
),
(
tabnanny.NannyNag(5, "testmsg", "testline"),
{'lineno': 5, 'msg': 'testmsg', 'line': 'testline'}
)
]
for nanny, expected in tests:
line_number = nanny.get_lineno()
msg = nanny.get_msg()
line = nanny.get_line()
with self.subTest(
line_number=line_number, expected=expected['lineno']
):
self.assertEqual(expected['lineno'], line_number)
with self.subTest(msg=msg, expected=expected['msg']):
self.assertEqual(expected['msg'], msg)
with self.subTest(line=line, expected=expected['line']):
self.assertEqual(expected['line'], line)
class TestCheck(TestCase):
"""Testing tabnanny.check()."""
def setUp(self):
self.addCleanup(setattr, tabnanny, 'verbose', tabnanny.verbose)
tabnanny.verbose = 0 # Forcefully deactivating verbose mode.
def verify_tabnanny_check(self, dir_or_file, out="", err=""):
"""Common verification for tabnanny.check().
Use this method to assert expected values of `stdout` and `stderr` after
running tabnanny.check() on given `dir` or `file` path. Because
tabnanny.check() captures exceptions and writes to `stdout` and
`stderr`, asserting standard outputs is the only way.
"""
with captured_stdout() as stdout, captured_stderr() as stderr:
tabnanny.check(dir_or_file)
self.assertEqual(stdout.getvalue(), out)
self.assertEqual(stderr.getvalue(), err)
def test_correct_file(self):
"""A python source code file without any errors."""
with TemporaryPyFile(SOURCE_CODES["error_free"]) as file_path:
self.verify_tabnanny_check(file_path)
def test_correct_directory_verbose(self):
"""Directory containing few error free python source code files.
Because order of files returned by `os.lsdir()` is not fixed, verify the
existence of each output lines at `stdout` using `in` operator.
`verbose` mode of `tabnanny.verbose` asserts `stdout`.
"""
with tempfile.TemporaryDirectory() as tmp_dir:
lines = [f"{tmp_dir!r}: listing directory\n",]
file1 = TemporaryPyFile(SOURCE_CODES["error_free"], directory=tmp_dir)
file2 = TemporaryPyFile(SOURCE_CODES["error_free"], directory=tmp_dir)
with file1 as file1_path, file2 as file2_path:
for file_path in (file1_path, file2_path):
lines.append(f"{file_path!r}: Clean bill of health.\n")
tabnanny.verbose = 1
with captured_stdout() as stdout, captured_stderr() as stderr:
tabnanny.check(tmp_dir)
stdout = stdout.getvalue()
for line in lines:
with self.subTest(line=line):
self.assertIn(line, stdout)
self.assertEqual(stderr.getvalue(), "")
def test_correct_directory(self):
"""Directory which contains few error free python source code files."""
with tempfile.TemporaryDirectory() as tmp_dir:
with TemporaryPyFile(SOURCE_CODES["error_free"], directory=tmp_dir):
self.verify_tabnanny_check(tmp_dir)
def test_when_wrong_indented(self):
"""A python source code file eligible for raising `IndentationError`."""
with TemporaryPyFile(SOURCE_CODES["wrong_indented"]) as file_path:
err = ('unindent does not match any outer indentation level'
' (<tokenize>, line 3)\n')
err = f"{file_path!r}: Indentation Error: {err}"
with self.assertRaises(SystemExit):
self.verify_tabnanny_check(file_path, err=err)
def test_when_tokenize_tokenerror(self):
"""A python source code file eligible for raising 'tokenize.TokenError'."""
with TemporaryPyFile(SOURCE_CODES["incomplete_expression"]) as file_path:
err = "('EOF in multi-line statement', (7, 0))\n"
err = f"{file_path!r}: Token Error: {err}"
with self.assertRaises(SystemExit):
self.verify_tabnanny_check(file_path, err=err)
def test_when_nannynag_error_verbose(self):
"""A python source code file eligible for raising `tabnanny.NannyNag`.
Tests will assert `stdout` after activating `tabnanny.verbose` mode.
"""
with TemporaryPyFile(SOURCE_CODES["nannynag_errored"]) as file_path:
out = f"{file_path!r}: *** Line 3: trouble in tab city! ***\n"
out += "offending line: '\\tprint(\"world\")\\n'\n"
out += "inconsistent use of tabs and spaces in indentation\n"
tabnanny.verbose = 1
self.verify_tabnanny_check(file_path, out=out)
def test_when_nannynag_error(self):
"""A python source code file eligible for raising `tabnanny.NannyNag`."""
with TemporaryPyFile(SOURCE_CODES["nannynag_errored"]) as file_path:
out = f"{file_path} 3 '\\tprint(\"world\")\\n'\n"
self.verify_tabnanny_check(file_path, out=out)
def test_when_no_file(self):
"""A python file which does not exist actually in system."""
path = 'no_file.py'
err = (f"{path!r}: I/O Error: [Errno {errno.ENOENT}] "
f"{os.strerror(errno.ENOENT)}: {path!r}\n")
with self.assertRaises(SystemExit):
self.verify_tabnanny_check(path, err=err)
def test_errored_directory(self):
"""Directory containing wrongly indented python source code files."""
with tempfile.TemporaryDirectory() as tmp_dir:
error_file = TemporaryPyFile(
SOURCE_CODES["wrong_indented"], directory=tmp_dir
)
code_file = TemporaryPyFile(
SOURCE_CODES["error_free"], directory=tmp_dir
)
with error_file as e_file, code_file as c_file:
err = ('unindent does not match any outer indentation level'
' (<tokenize>, line 3)\n')
err = f"{e_file!r}: Indentation Error: {err}"
with self.assertRaises(SystemExit):
self.verify_tabnanny_check(tmp_dir, err=err)
class TestProcessTokens(TestCase):
"""Testing `tabnanny.process_tokens()`."""
@mock.patch('tabnanny.NannyNag')
def test_with_correct_code(self, MockNannyNag):
"""A python source code without any whitespace related problems."""
with TemporaryPyFile(SOURCE_CODES["error_free"]) as file_path:
with open(file_path) as f:
tabnanny.process_tokens(tokenize.generate_tokens(f.readline))
self.assertFalse(MockNannyNag.called)
def test_with_errored_codes_samples(self):
"""A python source code with whitespace related sampled problems."""
# "tab_space_errored_1": executes block under type == tokenize.INDENT
# at `tabnanny.process_tokens()`.
# "tab space_errored_2": executes block under
# `check_equal and type not in JUNK` condition at
# `tabnanny.process_tokens()`.
for key in ["tab_space_errored_1", "tab_space_errored_2"]:
with self.subTest(key=key):
with TemporaryPyFile(SOURCE_CODES[key]) as file_path:
with open(file_path) as f:
tokens = tokenize.generate_tokens(f.readline)
with self.assertRaises(tabnanny.NannyNag):
tabnanny.process_tokens(tokens)
class TestCommandLine(TestCase):
"""Tests command line interface of `tabnanny`."""
def validate_cmd(self, *args, stdout="", stderr="", partial=False, expect_failure=False):
"""Common function to assert the behaviour of command line interface."""
if expect_failure:
_, out, err = script_helper.assert_python_failure('-m', 'tabnanny', *args)
else:
_, out, err = script_helper.assert_python_ok('-m', 'tabnanny', *args)
# Note: The `splitlines()` will solve the problem of CRLF(\r) added
# by OS Windows.
out = os.fsdecode(out)
err = os.fsdecode(err)
if partial:
for std, output in ((stdout, out), (stderr, err)):
_output = output.splitlines()
for _std in std.splitlines():
with self.subTest(std=_std, output=_output):
self.assertIn(_std, _output)
else:
self.assertListEqual(out.splitlines(), stdout.splitlines())
self.assertListEqual(err.splitlines(), stderr.splitlines())
def test_with_errored_file(self):
"""Should displays error when errored python file is given."""
with TemporaryPyFile(SOURCE_CODES["wrong_indented"]) as file_path:
stderr = f"{file_path!r}: Token Error: "
stderr += ('unindent does not match any outer indentation level'
' (<string>, line 3)')
self.validate_cmd(file_path, stderr=stderr, expect_failure=True)
def test_with_error_free_file(self):
"""Should not display anything if python file is correctly indented."""
with TemporaryPyFile(SOURCE_CODES["error_free"]) as file_path:
self.validate_cmd(file_path)
def test_command_usage(self):
"""Should display usage on no arguments."""
path = findfile('tabnanny.py')
stderr = f"Usage: {path} [-v] file_or_directory ..."
self.validate_cmd(stderr=stderr, expect_failure=True)
def test_quiet_flag(self):
"""Should display less when quite mode is on."""
with TemporaryPyFile(SOURCE_CODES["nannynag_errored"]) as file_path:
stdout = f"{file_path}\n"
self.validate_cmd("-q", file_path, stdout=stdout)
def test_verbose_mode(self):
"""Should display more error information if verbose mode is on."""
with TemporaryPyFile(SOURCE_CODES["nannynag_errored"]) as path:
stdout = textwrap.dedent(
"offending line: '\\tprint(\"world\")\\n'"
).strip()
self.validate_cmd("-v", path, stdout=stdout, partial=True)
def test_double_verbose_mode(self):
"""Should display detailed error information if double verbose is on."""
with TemporaryPyFile(SOURCE_CODES["nannynag_errored"]) as path:
stdout = textwrap.dedent(
"offending line: '\\tprint(\"world\")\\n'"
).strip()
self.validate_cmd("-vv", path, stdout=stdout, partial=True)