add tests coverage

.travis.yml

@@ -2,8 +2,12 @@ language: python
 python:
   - "2.7"
 
-install: 
+install:
   - "pip install ."
   - "pip install -r requirements.txt"
+  - "pip install coveralls"
 
-script: py.test -vvv
+script: coverage run --source=amodem tests/run.py
+
+after_success: 
+  - coveralls

tests/run.py

@@ -0,0 +1,2 @@
+import pytest
+pytest.main()