def test_plane(self): self.assertEqual(0, chart_area([2, 2, 2, 2, 2]))
def test_empty_chart(self): self.assertEqual(0, chart_area([]))
def test_mount_elbrus(self): self.assertEqual(25, chart_area([1, 2, 4, 8, 16, 6, 6, 8, 15, 7, 6, 7, 0]))
def test_castle_wall(self): self.assertEqual(1, chart_area([1, 2, 1, 2, 1, 2, 1, 2]))
def test_descending(self): self.assertEqual(0, chart_area([52, 43, 35, 28, 11]))
def test_ascending(self): self.assertEqual(0, chart_area([2, 3, 5, 8, 11]))