Add Ruby test suite to Travis

.travis.yml

@@ -1,13 +1,20 @@
-
 language: java
 sudo: false
-
-before_install:
-  - pip install --user virtualenv
-  - export PATH=$PATH:$HOME/.local/bin
-
 script:
   - ./go clean build
-  - "export PY_FILES_CHANGED=`git diff --name-only $TRAVIS_COMMIT_RANGE | grep ^py/`"
-  - "if [[ $PY_FILES_CHANGED == py/* ]]; then ./go py_prep_for_install_release; ./go //py:phantomjs_test:run; else echo no python files changed skipping python test suite; fi"
-
+  - |
+    export PY_FILES_CHANGED=`git diff --name-only $TRAVIS_COMMIT_RANGE | grep ^py/`
+    if [[ $PY_FILES_CHANGED == py/* ]]; then
+      pip install --user virtualenv
+      export PATH=$PATH:$HOME/.local/bin
+      ./go py_prep_for_install_release //py:phantomjs_test:run
+    else
+      echo 'no Python files changed - skipping Python test suite'
+    fi
+  - |
+    export RB_FILES_CHANGED=`git diff --name-only $TRAVIS_COMMIT_RANGE | grep ^rb/`
+    if [[ $RB_FILES_CHANGED == rb/* ]]; then
+      ./go //rb:unit-test //rb:phantomjs-test
+    else
+      echo 'no Ruby files changed - skipping Ruby test suite'
+    fi