travis : unit tests will run with and without libyaml (#2024)

* travis : unit tests will run with and without libyaml

* travis : fixed package that are installed

.travis.yml

@@ -6,7 +6,8 @@ python:
   - 2.7
 
 env:
-  - TEST_SUITE=unit
+  - TEST_SUITE=unit CYAML=true
+  - TEST_SUITE=unit CYAML=false
   - TEST_SUITE=flake8
   - TEST_SUITE=doc
 
@@ -24,6 +25,7 @@ addons:
   apt:
     packages:
       - graphviz
+      - libyaml-dev
 
 # Install various dependencies
 install:
@@ -31,6 +33,7 @@ install:
   - pip install flake8
   - pip install sphinx
   - pip install mercurial
+  - if [[ $CYAML == true ]]; then pip install --global-option "--with-libyaml" pyyaml; fi
 
 before_script:
   # Need this for the git tests to succeed.
@@ -43,7 +46,7 @@ before_script:
 script: share/spack/qa/run-$TEST_SUITE-tests
 
 after_success:
-  - if [[ $TEST_SUITE == unit && $TRAVIS_PYTHON_VERSION == 2.7 ]]; then coveralls; fi
+  - if [[ $TEST_SUITE == unit && $CYAML == false && $TRAVIS_PYTHON_VERSION == 2.7 ]]; then coveralls; fi
 
 notifications:
   email: