Merge branch 'tests-gardening' into 'develop'

declearn/communication/api/_server.py

declearn/communication/websockets/_server.py

test/communication/test_exchanges.py

test/communication/test_routines.py

test/communication/test_server.py

test/conftest.py

test/functional/test_main.py

test/functional/test_regression.py

test/model/test_tflow.py

test/model/test_torch.py

tox.ini