Add tests for hass.io (#817)

* Add tests for hass.io

* Fix folder

* Fix test command

tox.ini

@@ -1,10 +1,11 @@
 [tox]
-envlist = lint
+envlist = lint, tests
 
 [testenv]
 deps =
     flake8==3.6.0
     pylint==2.1.1
+    pytest==4.0.0
     -r{toxinidir}/requirements.txt
 
 [testenv:lint]
@@ -13,3 +14,8 @@ ignore_errors = True
 commands =
      flake8 hassio
      pylint --rcfile pylintrc hassio
+
+[testenv:tests]
+basepython = python3
+commands =
+    pytest --duration=10 tests