Merge pull request #974 from willingc/travis-config

Refactor travis config for more efficient builds

.travis.yml

@@ -1,23 +1,29 @@
 # http://travis-ci.org/#!/jupyter/jupyterhub
 language: python
-sudo: false
 python:
-    - 3.7-dev
+    - nightly
     - 3.6
     - 3.5
     - 3.4
     - 3.3
+
+
+# installing dependencies
 before_install:
     - npm install
     - npm install -g configurable-http-proxy
     - git clone --quiet --depth 1 https://github.com/minrk/travis-wheels travis-wheels
 install:
     - pip install --pre -f travis-wheels/wheelhouse -r dev-requirements.txt .
+
+# running tests
 script:
-    - travis_retry py.test --cov=jupyterhub jupyterhub/tests -v
+    - pytest --maxfail=2 --cov=jupyterhub jupyterhub/tests
 after_success:
     - codecov
+
 matrix:
+  fast_finish: true
   include:
     - python: 3.6
       env: JUPYTERHUB_TEST_SUBDOMAIN_HOST=http://127.0.0.1.xip.io:8000