Run self-check on Windows as part of CI (#11909)

As discussed in #11895, mypy's test suite currently does not pass a mypy self-check when run on Windows. This should hopefully be fixed by python/typeshed#6812, but running a self-check on Windows as part of the CI tests should help avoid this issue in the future.

.github/workflows/test.yml

@@ -75,11 +75,16 @@ jobs:
  toxenv: py36
  tox_extra_args: "-n 2 mypyc/test/test_run.py mypyc/test/test_external.py"
  debug_build: true
- - name: Type check our own code
+ - name: Type check our own code (py37-ubuntu)
  python: '3.7'
  arch: x64
  os: ubuntu-latest
  toxenv: type
+ - name: Type check our own code (py37-windows-64)
+ python: '3.7'
+ arch: x64
+ os: windows-latest
+ toxenv: type
  - name: Code style with flake8
  python: '3.7'
  arch: x64

mypy/util.py

@@ -517,6 +517,8 @@ def hash_digest(data: bytes) -> str:
 
 def parse_gray_color(cup: bytes) -> str:
  """Reproduce a gray color in ANSI escape sequence"""
+ if sys.platform == "win32":
+ assert False, "curses is not available on Windows"
  set_color = ''.join([cup[:-1].decode(), 'm'])
  gray = curses.tparm(set_color.encode('utf-8'), 1, 89).decode()
  return gray
@@ -580,7 +582,7 @@ def initialize_win_colors(self) -> bool:
 
  def initialize_unix_colors(self) -> bool:
  """Return True if initialization was successful and we can use colors, False otherwise"""
- if not CURSES_ENABLED:
+ if sys.platform == "win32" or not CURSES_ENABLED:
  return False
  try:
  # setupterm wants a fd to potentially write an "initialization sequence".