remove python 3.7 testing

Author: illagrenan

.travis.yml

@@ -5,15 +5,15 @@ python:
   - "3.5-dev" # 3.5 development branch
   - "3.6"
   - "3.6-dev" # 3.6 development branch
-  - "3.7-dev" # 3.7 development branch
-  - "nightly" # currently points to 3.7-dev
 env:
   - PYTHONUNBUFFERED="1"
 install:
     - pip install --isolated --no-input --compile --exists-action=a --disable-pip-version-check --use-wheel --no-cache-dir -r ./requirements/dev.txt
     - pip install --isolated --no-input --compile --exists-action=a --disable-pip-version-check --use-wheel --no-cache-dir --upgrade setuptools wheel
 script:
-    - inv test
+    - inv clean
+    - inv check
     - inv build
+    - inv test-install
 notifications:
     email: false