unittests/python3.py

#!/usr/bin/env vpython3
# Copyright 2018 The LUCI Authors. All rights reserved.
# Use of this source code is governed under the Apache License, Version 2.0
# that can be found in the LICENSE file.

"""General tests during the python3 transition."""

from __future__ import annotations

import ast
import difflib
import linecache
import os
import unittest
import warnings

from lib2to3 import refactor

from libfuturize.fixes import (lib2to3_fix_names_stage1,
                               libfuturize_fix_names_stage1)

import test_env


def _py_files():
  for (dirpath, dirnames, filenames) in os.walk(test_env.ROOT_DIR):
    try:
      dirnames.remove('.recipe_deps')
    except ValueError:
      pass
    yield from (
      os.path.join(dirpath, n)
      for n in filenames
      if n.endswith('.py')
    )

class _2to3TestTool(refactor.RefactoringTool):
  def __init__(self, test_fail, *args, **kwargs):
    self.test_fail = test_fail
    super().__init__(*args, **kwargs)


  @staticmethod
  def diff_texts(a, b, filename):
    """Return a unified diff of two strings."""
    a = a.splitlines()
    b = b.splitlines()
    return difflib.unified_diff(
        a, b, filename, filename,
        "(original)", "(refactored)",
        lineterm="")

  def print_output(self, old_text, new_text, filename, equal):
    if equal:
      return
    self.test_fail('\n' + '\n'.join(self.diff_texts(
        old_text, new_text, filename)))


class Py3Syntax(unittest.TestCase):
  def test_python3_syntax(self):
    for fname in _py_files():
      with self.subTest(fname=fname):
        with open(fname) as sourcef:
          with warnings.catch_warnings(record=True) as warn_msgs:
            ast.parse(sourcef.read(), fname, type_comments=True,
                      feature_version=(3, 8))
        if warn_msgs:
          fmt = 'line {msg.lineno}: {category}: {msg.message}\n  {line}'
          self.fail('\n' + '\n'.join(
              fmt.format(
                  msg=msg,
                  category=msg.category.__name__,
                  line=linecache.getline(msg.filename, msg.lineno)
              ) for msg in warn_msgs
          ))

  def test_futurize_stage1(self):
    avail_fixes = lib2to3_fix_names_stage1 | libfuturize_fix_names_stage1
    tool = _2to3TestTool(self.fail, avail_fixes)

    for fname in _py_files():
      with self.subTest(fname=fname):
        with open(fname) as f:
          data = f.read()
        if '#py3Only\n' in data:
          continue  # this file has marked itself as python3-only compatible.
        # extra newline is cargo-culted from tool.refactor_file.
        tool.refactor_string(data+'\n', fname)


if __name__ == '__main__':
  test_env.main()