How to handle a testing only python package dependency

G'day fellow hackers,

to finally merge the work of one of my GSoC students we are trying to
figure out how to handle a new test framework only python package
dependency. Note that the package is a purely optional dependency and not
required to run our normal test cases. The dependency in question is testx
which again has two dependencies:

textX==2.0.1
  - Arpeggio [required: >=1.9.0, installed: 1.9.0]
  - click [required: ==7.0, installed: 7.0]

What is our policy about python packages that are actually not needed for
an installed LibreOffice?
My current solution would be to add an explicit ImportError check in the
script and tell the person calling the script to install the package. As
this is mostly something for a few selected QA team members this seems like
an acceptable solution.

Any other solutions/opinions?

Markus