@Test
public void testRemoveNode() throws NodeNotExistsExeption{

	Graph<String> graph = new Graph<String>();
	graph.addNode("n1");
	graph.addNode("n2");
	graph.addNode("n3");
	graph.addNode("n4");
	graph.addNode("n5");
	graph.addNode("n6");
	graph.addEdge("n2", "n3");
	graph.addEdge("n3", "n4");
	graph.addEdge("n1", "n5");
	graph.addEdge("n2", "n6");
	printGraph(graph, "testRemoveNode1");
	graph.removeNode("n4");
	assertNull(graph.findNode("n2"));
	assertNotNull(graph.findNode("n6"));
	printGraph(graph, "testRemoveNode2");
}