Bug#1040334: facet-analyser - build-depends on conflicting packages

[Drew Parsons]

Source: facet-analyser
Followup-For: Bug #1040334

As far as I can tell facet-analyser does not actually need
python3-paraview, except for two build-time tests
(basicPluginTest01 pvsm2webgl.py, and basicPluginTest02 pvsm2x3d.py)

I believe there is no conflict between paraview-dev and libvtk9-dev
themselves. Certainly there's no file conflict and both packages can
be installed at the same time.  The conflict is only in the python
module vtkmodules (libvtk9-dev Depends: python3-vtk9 but paraview-dev
does not depend on python3-paraview).

If that's the case, then a workaround is to simply disable these two
tests during build and drop the python3-paraview Build-Depends.

It should be possible to run the test scripts at runtime (i.e. in
debci). Likely not via cmake but invoked manually from debian/tests.

It might be worth asking facet-analyser upstream how they deal with
the issue. Debian did not invent the problem. paraview upstream
resolutely refuses to align paraview with a released version of VTK,
but ITK (libinsighttoolkit5-dev) uses VTK as released. So
facet-analyser upstream must be facing the same problem. How do they
handle it?

Drew