def test_method_has_key_of_Graph(self):
"""Test case:
* check that node is a Node object
* if the key is available in the dict, return True
"""
g = Graph()
with self.assertRaises(TypeError) as context:
g.has_key('A')
self.assertTrue('A is not of type Node' in context.exception)
n1 = Node('A')
g.addNode(n1)
self.assertTrue(g.has_key(n1))
