3 Axis and Backpack Tests

[sanssecours]

Hi @bertlderschreckliche,

I just looked at your latest changes to the main branch. There were some minor problems regarding the formatting that I fixed in this PR. However, If I run:

just check

then Flake8 reports the following problems:

./icotest/test/test_sth.py:145:5: F841 local variable 'test_acc_bias' is assigned to but never used
./icotest/test/test_sth.py:249:5: F841 local variable 'acc_bias' is assigned to but never used
./icotest/test/test_sth.py:250:5: F841 local variable 'acc_noise' is assigned to but never used

Can you please try to fix this problem?