@Test
public void testTopoSortVertexOfE() {

	Vector<Vertex<String>> result = connect.topoSort(a);
	assertTrue(result.get(0) == a);
	assertTrue(result.get(1) == c);
	assertTrue(result.get(2) == b);
	assertTrue(result.get(3) == d);
	assertTrue(result.get(result.size()-1) == f);
}