Avoid subprocess for Windows tests

[dagewa]

Two tests were failing on Windows because subprocess does not resolve .bat in the dispatcher name.

1. test_plot_reflections.py is converted here to use procrunner, which fixes that issue.
2. test_find_spots_server_client.py is disabled on Windows, because dials.find_spots_server does not work there.

[codecov]

Codecov Report

Merging #1599 (dbac4d1) into master (7613ba6) will decrease coverage by 0.00%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master    #1599      +/-   ##
==========================================
- Coverage   66.62%   66.62%   -0.01%     
==========================================
  Files         614      614              
  Lines       68725    68727       +2     
  Branches     9567     9568       +1     
==========================================
  Hits        45789    45789              
- Misses      21008    21009       +1     
- Partials     1928     1929       +1     

[Anthchirp]

dials.find_spots_server does not work there.

...why is that?

[dagewa]

On an account with Administrator privileges to avoid issues with opening sockets, I still get:

c:\Users\fcx32934\sw\cctbx>dials.find_spots_server
Sat Feb 20 11:25:29 2021 Serving 20 processes on port 1701
Traceback (most recent call last):
  File "c:\Users\fcx32934\sw\cctbx\build\..\modules\dials\command_line\find_spots_server.py", line 344, in <module>
    run()
  File "c:\Users\fcx32934\sw\cctbx\conda_base\lib\contextlib.py", line 75, in inner
    return func(*args, **kwds)
  File "c:\Users\fcx32934\sw\cctbx\build\..\modules\dials\command_line\find_spots_server.py", line 340, in run
    main(params.nproc, params.port)
  File "c:\Users\fcx32934\sw\cctbx\build\..\modules\dials\command_line\find_spots_server.py", line 318, in main
    proc.start()
  File "c:\Users\fcx32934\sw\cctbx\conda_base\lib\multiprocessing\process.py", line 121, in start
    self._popen = self._Popen(self)
  File "c:\Users\fcx32934\sw\cctbx\conda_base\lib\multiprocessing\context.py", line 224, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "c:\Users\fcx32934\sw\cctbx\conda_base\lib\multiprocessing\context.py", line 327, in _Popen
    return Popen(process_obj)
  File "c:\Users\fcx32934\sw\cctbx\conda_base\lib\multiprocessing\popen_spawn_win32.py", line 93, in __init__
    reduction.dump(process_obj, to_child)
  File "c:\Users\fcx32934\sw\cctbx\conda_base\lib\multiprocessing\reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)
TypeError: Please report this error to dials-support@lists.sourceforge.net: cannot pickle '_thread.lock' object

c:\Users\fcx32934\sw\cctbx>Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "c:\Users\fcx32934\sw\cctbx\conda_base\lib\multiprocessing\spawn.py", line 107, in spawn_main
    new_handle = reduction.duplicate(pipe_handle,
  File "c:\Users\fcx32934\sw\cctbx\conda_base\lib\multiprocessing\reduction.py", line 79, in duplicate
    return _winapi.DuplicateHandle(
PermissionError: [WinError 5] Access is denied

[dagewa]

Actually it's exactly the same error on my non-admin account. Looks like the usual Windows multiprocessing issues.

[Anthchirp]

ah okay, so it's just exactly the same problem as on MacOS with Python 3.8+