Tests(CI): Explicitly list python versions at Travis CI

diff --git a/.travis.yml b/.travis.yml
index d62df94e502f6fd2f85ba04bb4c2fd5a2ce24f82..e2743b2e4876c2a52e295220801d8af9c7fa0212 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,18 +12,26 @@ sudo: required
 language: python
 
 python:
-  - "3.6"
+  - "2.7"
 
 cache: pip
 
-env:
-  - TOXENV=py27
-  - TOXENV=py33
-  - TOXENV=py34
-  - TOXENV=py35
-  - TOXENV=py36
-  - TOXENV=py27-flake8
-  - TOXENV=py34-flake8
+matrix:
+  include:
+  - python: "2.7"
+    env: TOXENV=py27
+  - python: "3.3"
+    env: TOXENV=py33
+  - python: "3.4"
+    env: TOXENV=py34
+  - python: "3.5"
+    env: TOXENV=py35
+  - python: "3.6"
+    env: TOXENV=py36
+  - python: "2.7"
+    env: TOXENV=py27-flake8
+  - python: "3.4"
+    env: TOXENV=py34-flake8
 
 install:
   - travis_retry pip install tox