matrix setup

.travis.yml

@@ -1,12 +1,11 @@
 language: python
-python:
-  - "2.7"
-  - "3.4"
-  - "3.5"
-  - "3.6"
-  # - "3.7-dev"
-  # - "pypy"
-  # - "pypy3" # TODO: pkg_config issues
+
+matrix:
+  include:
+    - python: "2.7"
+    - python: "3.4"
+    - python: "3.5"
+    - python: "3.6"
 
 # command to install dependencies
 install:
@@ -17,8 +16,6 @@ install:
 jobs:
   include:
     - stage: Style Tests ✨
-      python: "3.6"
       script: pipenv run flake8
     - stage: Main Test Suite ✨✨
-      python: "3.6"
       script: pipenv run pytest tests