Add a job to run unit tests

.travis.yml

@@ -1,17 +1,21 @@
 language: python
 
+git:
+  quiet: true
+
 cache: pip
 before_cache:
   - rm ~/.cache/pip/log/debug.log
 
-python:
-  - "3.6"
+matrix:
+  include:
+  - name: "Lint check"
+    python: "3.6"
+    install: pip install --quiet --upgrade cardboardlint pylint
+    env: TEST_SUITE="lint"
+  - name: "Unit tests"
+    python: "3.6"
+    install: pip install --quiet -r requirements.txt
+    env: TEST_SUITE="unittest"
 
-install:
-  - pip install --upgrade cardboardlint pylint
-
-script:
-  # Run cardboardlinter, in case of pull requests
-  - if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then
-      cardboardlinter --refspec $TRAVIS_BRANCH -n auto;
-    fi
+script: ./.travis/script

.travis/script

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -ex
+
+if [[ ( "$TRAVIS_PULL_REQUEST" != "false" ) && ( "$TEST_SUITE" == "lint" ) ]]; then
+  # Run cardboardlinter, in case of pull requests
+  cardboardlinter --refspec $TRAVIS_BRANCH -n auto
+fi
+
+if [[ "$TEST_SUITE" == "unittest" ]]; then
+  # Run tests on all pushes
+  python -m unittest
+fi