correct tests

Author: rflamary

.github/workflows/pythonpackage.yml

@@ -27,9 +27,9 @@ jobs:
         # stop the build if there are Python syntax errors or undefined names
         flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
         # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-        flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+        flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics        
     - name: Test with pytest
       run: |
         pip install pytest "pytest-cov<2.6"
-        pip install .
+        python setup.py develop
         python -m pytest -v test/ ot/ --doctest-modules --ignore ot/gpu/ --cov=ot