add numpy in extra_requires for test suite

.gitlab-ci.yml

@@ -8,7 +8,7 @@ test-evalhyd-python:
     # print Python version
     - python --version
     # compile and install package
-    - python -m pip install --user .
+    - python -m pip install --user .[tests]
     # make sure package can be imported and check version
     - python -c "import evalhyd;print(evalhyd.__version__)"
     # run test suite

setup.py

@@ -44,5 +44,6 @@ setup(
     long_description='An evaluator for streamflow predictions.',
     ext_modules=ext_modules,
     cmdclass={'build_ext': build_ext},
+    extras_require={"tests": "numpy>=1.16"},
     zip_safe=False,
 )