fix py2.7

.travis.yml

@@ -23,7 +23,6 @@ install:
   - pip install pycodestyle
   - pip install flake8
   - pip install codecov
-  - if [[ $TRAVIS_PYTHON_VERSION == 2.7 ]]; then pip install "pytest<5.0"; fi
 script:
   - if [[ $TRAVIS_PYTHON_VERSION != 2.7 ]]; then pycodestyle .; fi
   - if [[ $TRAVIS_PYTHON_VERSION != 2.7 ]]; then flake8 .; fi

setup.py

@@ -25,7 +25,7 @@ url = 'https://github.com/rusty1s/pytorch_scatter'
 
 install_requires = []
 setup_requires = ['pytest-runner']
-tests_require = ['pytest', 'pytest-cov']
+tests_require = ['pytest<5.0', 'pytest-cov']
 
 setup(
     name='torch_scatter',