tests/test-check-pyflakes.t

tests: stabilize test-patch.t on Windows

$PYTHON needs to be quoted when invoking with cmd.exe, because the value expands
to c:/Python27/python.exe, which seems to be interpreted as 'c' being a command.
We can't just convert to '\', because there are a few places that run $PYTHON
directly in MSYS.  If unquoted there, it results in c:Python27python.exe being
run.  I wonder if we should bake the quotes into the environment variable to
avoid this.

It also wasn't happy with the quoting around exit1.py:

  c:/Python27/python.exe: can't open file ''$TESTTMP/d/exit1.py'': [Errno 22] Invalid argument

#require test-repo pyflakes hg10

  $ . "$TESTDIR/helpers-testrepo.sh"

run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)

  $ cat > test.py <<EOF
  > print(undefinedname)
  > EOF
  $ pyflakes test.py 2>/dev/null | "$TESTDIR/filterpyflakes.py"
  test.py:1: undefined name 'undefinedname'
  
  $ cd "`dirname "$TESTDIR"`"

  $ testrepohg locate 'set:**.py or grep("^#!.*python")' \
  > -X hgext/fsmonitor/pywatchman \
  > -X mercurial/pycompat.py -X contrib/python-zstandard \
  > -X mercurial/thirdparty/cbor \
  > -X mercurial/thirdparty/concurrent \
  > -X mercurial/thirdparty/zope \
  > 2>/dev/null \
  > | xargs pyflakes 2>/dev/null | "$TESTDIR/filterpyflakes.py"