two errors in prepost that make the test fail

https://gitlab.windenergy.dtu.dk/toolbox/WindEnergyToolbox/builds/2374

I have change the test from python setup.py test to python3 -m coverage run -m py.test

I do not know if it is really necessary, but I could not make it work straight away with the old test syntax And I do not know why it is failing here and not there