Set up new unittest system

[TheDuckCow]

Currently, all two tests pass over all targeted versions of blender. See some different sample commands below (may eventually add this into a README, but that will be a later PR).

cmd: python3 run_tests.py

-------------------------------------------------------------------------------
bversion   	ran_tests	ran	failed	errors
-------------------------------------------------------------------------------
(3.6.0)   	all_tests	2	0	No errors

cmd: python3 run_tests.py -a

-------------------------------------------------------------------------------
bversion   	ran_tests	ran	failed	errors
-------------------------------------------------------------------------------
(3.6.0)   	all_tests	2	0	No errors
(3.5.1)   	all_tests	2	0	No errors
(3.4.0)   	all_tests	2	0	No errors
(3.2.1)   	all_tests	2	0	No errors
(3.3.1)   	all_tests	2	0	No errors
(3.1.0)   	all_tests	2	0	No errors
(3.0.0)   	all_tests	2	0	No errors
(2.93.0)   	all_tests	2	0	No errors
(2.90.1)   	all_tests	2	0	No errors
(2.80.75)   	all_tests	2	0	No errors

cmd: python3 run_tests.py -t test_enable -v 3.6,2 (showing up running a specific test, and specific blender versions)

-------------------------------------------------------------------------------
bversion   	ran_tests	ran	failed	errors
-------------------------------------------------------------------------------
(3.6.0)   	test_enable	1	0	No errors
(2.93.0)   	test_enable	1	0	No errors
(2.90.1)   	test_enable	1	0	No errors
(2.80.75)   	test_enable	1	0	No errors

Relates to #424 but does not itself complete the change, as individual tests still need to be migrated.

[TheDuckCow]

FYI that this isn't yet using the new build system, so in the meantime you'll have to modify the line:
COMPILE_CMD = ["./compile.sh", "-fast"] in the run_tests.py for now.

Once #422 is merged, we'll update the script here.

[StandingPadAnimations]

I think I'm missing something, cause my output is barebones when running the test scripts. I did get the following error when running on Arch Linux, but it didn't seem to do much:

Failed to open dir (No such file or directory): /run/user/1000/gvfs/

/run/user is a Flatpak think so I don't know why that happened (since I'm using the native Blender package)

[TheDuckCow]

Happy to debug live in the later part of the dev team meeting in ~1h 45m, can you tell which line this is hailing from?

I realize that nothing stops you from trying to use the bpy-build command, if you want to locally swap for those args in the run_tests.py file COMPILE_CMD command args list.

[StandingPadAnimations]

Happy to debug live in the later part of the dev team meeting in ~1h 45m, can you tell which line this is hailing from?

I'm not sure; doesn't impact much though. I'll test with bpy-build later today.

[TheDuckCow]

Any newfound luck with the latest bpy build structure @StandingPadAnimations? If not, I can separatley try to test on another machine in a fresh space.

[StandingPadAnimations]

Haven't tested with bpy-build yet, might try later today

[StandingPadAnimations]

Still get the error with bpy-build (had to do a local merge for bpy-build). Like I said, it doesn't seem to impact anything (and frankly it's a little confusing to me since I'm not running Blender as a Flatpak, but /run is normally associated with Flatpaks).

This is my test output:

-------------------------------------------------------------------------------
bversion   	ran_tests	ran	failed	errors
-------------------------------------------------------------------------------
(3.6.0)   	all_tests	2	0	No errors