def test_get_first(self):
l = DoublyLinkedList()
self.assertRaises(IndexError, l.get_first)
for i in range(50):
l.add_first(i)
self.assertEqual(l.get_first(), i)
def test_add(self):
l = DoublyLinkedList()
self.assertTrue(l.is_empty())
l.add(0)
self.assertEqual(l.get_first(), 0)
self.assertEqual(l.get_last(), 0)
self.assertEqual(l.get_elements(), 1)
l.add(1)
self.assertEqual(l.get_last(), 1)
self.assertNotEqual(l.get_first(), 1)
self.assertEqual(l.get_first(), 0)
self.assertEqual(l.get_elements(), 2)
l.add(2)
self.assertEqual(l.get_last(), 2)
self.assertEqual(l.get_first(), 0)
self.assertEqual(l.index_of(1), 1)
self.assertEqual(l.get_elements(), 3)
self.assertFalse(l.is_empty())
def test_remove_first(self):
l = DoublyLinkedList()
self.assertTrue(l.is_empty())
l.add('a')
l.add('b')
l.add('c')
self.assertEqual(len(l), 3)
l.remove_first()
self.assertEqual(len(l), 2)
self.assertEqual(l.get_first(), 'b')
l.remove_first()
self.assertEqual(len(l), 1)
self.assertEqual(l.get_first(), 'c')
l.remove_first()
self.assertRaises(IndexError, l.remove_first)
self.assertEqual(len(l), 0)
self.assertTrue(l.is_empty())
def test_delete(self):
l = DoublyLinkedList()
self.assertRaises(ValueError, l.delete, 0)
for i in range(5):
l.add(i)
self.assertTrue(l.contains(i))
l.delete(2)
self.assertFalse(l.contains(2))
self.assertEqual(l.index_of(1), 1)
self.assertEqual(l.index_of(3), 2)
self.assertEqual(l.get_elements(), 4)
l.delete(0)
self.assertFalse(l.contains(0))
self.assertEqual(l.get_first(), 1)
self.assertEqual(l.index_of(3), 1)
self.assertEqual(l.get_elements(), 3)
l.delete(4)
self.assertFalse(l.contains(4))
self.assertEqual(l.get_last(), 3)
self.assertEqual(l.get_first(), 1)
self.assertRaises(ValueError, l.index_of, 4)
self.assertEqual(l.get_elements(), 2)
l.delete(1)
self.assertFalse(l.contains(1))
self.assertEqual(l.get_first(), 3)
self.assertEqual(l.get_last(), 3)
self.assertEqual(l.get_elements(), 1)
l.delete(3)
self.assertTrue(l.is_empty())
self.assertEqual(l.get_elements(), 0)