Explain how to test iface in PyQGIS testing framework

[DelazJ]

Description

As per #3621 (comment)
One question.
How can I make it detect iface, without generating a standlone application or my own iface?

from qgis.utils import iface

  iface.mapCanvas().layers()
Exception raised:
  Traceback (most recent call last):
    File "/usr/lib/python3.6/doctest.py", line 1330, in __run
      compileflags, 1), test.globs)
    File "<doctest default[0]>", line 3, in <module>
      iface.mapCanvas().layers()
  AttributeError: 'NoneType' object has no attribute 'mapCanvas'

and processing too:

ModuleNotFoundError: No module named 'processing'

Currently code samples making these calls are made untested, hence potentially not reliable in the long run

[All4Gis]

Any updates on this @DelazJ ?

[DelazJ]

Euhhh... Unfortunately, none!
I don't have the necessary background to look into this issue so nothing would come from me. Since this is an issue we'll face if we want to have the testing infrastructure fully operational, the report was to attract skilled people. But seems that it fails...
Sorry.