add bad login catcher

tests/test_pycarwings2.py

@@ -1,7 +1,16 @@
 #!/usr/bin/env python
 
-import pycarwings2
 import time
+import logging
+import sys
+import pycarwings2
+import pytest
+
+logging.basicConfig(stream=sys.stdout, level=logging.ERROR)
+
+def test_bad_password():
+    with pytest.raises(pycarwings2.CarwingsError) as excinfo:
+	s =  pycarwings2.Session("user@domain.com", "password", "NE")
+	l = s.get_leaf()
+    assert 'INVALID' in str(excinfo.value)
 
-s = pycarwings2.Session("user@domain.com", "password")
-l = s.get_leaf()