MAINT: Better test fixtures

[larsoner]

Try out nipy/PySurfer#289

[larsoner]

Failed but the traceback was truncated, restarting

[larsoner]

This does not fix the problem:

https://dev.azure.com/mne-tools/mne-python/_build/results?buildId=5679&view=logs&j=b195a6e3-7484-5943-e627-0b35c27605d6&t=6dcb3581-08d4-5e76-74f2-6edaf20ff912&l=225

  File "D:\a\1\s\conda\lib\site-packages\tvtk\pyface\ui\qt4\QVTKRenderWindowInteractor.py", line 370 in paintEvent
  File "D:\a\1\s\conda\lib\site-packages\tvtk\pyface\ui\qt4\scene.py", line 69 in paintEvent
  File "D:\a\1\s\conda\lib\site-packages\pyface\ui\qt4\gui.py", line 85 in process_events
  File "D:\a\1\s\conda\lib\site-packages\surfer\viz.py", line 183 in _force_render
  File "D:\a\1\s\conda\lib\site-packages\surfer\viz.py", line 550 in _toggle_render
  File "D:\a\1\s\conda\lib\site-packages\surfer\viz.py", line 487 in __init__
  File "D:\a\1\s\mne\viz\_3d.py", line 2385 in plot_vector_source_estimates

So we have some persistent problem with TVTK where paintEvent tries to draw something that should not be drawable.

I'll try tweaking mayavi again, I had another idea for what might help. We'll see!

[codecov]

Codecov Report

Merging #7358 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #7358      +/-   ##
==========================================
+ Coverage   89.96%   89.96%   +<.01%     
==========================================
  Files         451      451              
  Lines       81630    81847     +217     
  Branches    12956    12982      +26     
==========================================
+ Hits        73435    73631     +196     
- Misses       5372     5386      +14     
- Partials     2823     2830       +7

[larsoner]

After many restarts, I was finally able to see the problem even on my mayavi branch:

Thread 0x0000055c (most recent call first):
  File "D:\a\1\s\conda\lib\site-packages\tvtk\pyface\ui\qt4\QVTKRenderWindowInteWindows fatal exception: raccess violationa

ctor.py", line 379 in paintEvent

So it's still the paintEvent/self._RenderWindow.Render() call breaking things.

Time to try another thing, which is adding self._Iren.SetRenderWindow(None) in the Finalize call. But this is almost just a shot in the dark...

[larsoner]

Okay I new think the problem is more likely that there is some VTK object that tries to draw before the window is closed (which is reasonable behavior) but some underlying memory (e.g., NumPy array) has been GC'ed so it gets an access violation.

Not sure how best to track that down, but I'll see if upping the VTK verbosity and running with -s helps.

[larsoner]

Okay I'm abandoning the PySurfer/mayavi stuff, leaving #7294 as a reminder of the failures.

I did find some minor issues by testing with -vs on Azure, though, so I'm changing the title and just making this a maintenance PR to improve our testing a bit.