[QGIS-Developer] testing processing algorithms with PostgreSQL provider

[Sandro Santilli]

While working on improved heuristics with ExtractWithinDistance
processing algorithm [1] I stumbled upon a possible bug [2] and
trying to find a good way to add a test for it.

My understanding of the "Processing Algorithms Testing" page [3]
is that the yaml files used for testing can only use FILES as inputs
to the processing algorithm, but in order for the bug I found to be
exposed I need them to use the PostgreSQL provider.

My questions are:

  - Do you confirm only files can be used as input ?

  - What's the best way to test the functionality of
    src/analysis/processing/qgsalgorithmdistancewithin.cpp
    when used against different providers ?

[1] https://github.com/qgis/QGIS/pull/45339
[2] https://github.com/qgis/QGIS/issues/45352
[3] https://docs.qgis.org/3.16/en/docs/developers_guide/processingtesting.html

--strk;

  Libre GIS consultant/developer
  https://strk.kbt.io/services.html