fix bug

Author: rusty1s

.travis.yml

@@ -113,7 +113,7 @@ install:
   - pip install flake8
   - pip install codecov
   - pip install scipy==1.4.1
-  - python setup.py .[test]
+  - pip install .[test]
 script:
   - flake8 .
   - python setup.py test