travis config: report to coveralls.io

.travis.yml

@@ -2,11 +2,22 @@ language: python
 python:
     - "2.7"
     - "2.6"
-install:
-    - travis_retry pip install .
-    - travis_retry pip install pylast flask
-    - "if [[ $TRAVIS_PYTHON_VERSION == '2.6' ]]; then pip install unittest2; fi"
-script: nosetests
+
 branches:
     only:
         - master
+
+install:
+    - travis_retry pip install .
+    - travis_retry pip install pylast flask
+    # unittest backport on Python < 2.7
+    - "[[ $TRAVIS_PYTHON_VERSION == '2.6' ]] && pip install unittest2"
+
+script: nosetests --with-coverage --cover-package=beets
+
+# coveralls.io reporting, using https://github.com/coagulant/coveralls-python
+# Only report coverage for one version.
+before_script:
+    - "[[ $TRAVIS_PYTHON_VERSION == '2.7' ]] && pip install coveralls"
+after_success:
+    - "[[ $TRAVIS_PYTHON_VERSION == '2.7' ]] && coveralls"