@Test
	/**
	 *  Test that a path exists between any two stations in the metro system.
	 */
	public void testPathExists() {
		ArrayList<Integer> path;
		
		Set<Integer> addedStationsIndex = mmap.getMetroGraph().vertexSet();
		for (int i=1; i<=totalStationCount; i++) {
			for (int j=1; j<=totalStationCount; j++) {
				if (i != j && addedStationsIndex.contains(i) && addedStationsIndex.contains(j)) {
					// 1. Test for path existence between stations (i, j)
					path = mmap.getQuickestRoute(i, j);
					assertNotNull(path);
					assertTrue(!path.isEmpty());
					// 2. Test that station i and j are contained in this path
					assertTrue(path.contains(i) && path.contains(j));
					// 3. Test that station i and j are the head and tail of the path respectively
					assertTrue(path.get(0) == i && path.get(path.size()-1) == j);
				}
			}
		}
	}