def test_count(self):
alist = doublelist.DoubleList()
self.assertEqual(alist.count(), 0)
alist.insert_head(doublelist.Node(1))
alist.insert_head(doublelist.Node(2))
alist.insert_head(doublelist.Node(3))
self.assertEqual(alist.count(), 3)
def test_insert_tail(self):
alist = doublelist.DoubleList()
tail_node = doublelist.Node('head')
alist.insert_tail(doublelist.Node('not tail'))
alist.insert_tail(tail_node)
self.assertEqual(alist.nil.prev, tail_node)
self.assertNotEqual(alist.nil.next, tail_node)
self.assertEqual(alist.length, 2)
def test_insert_head(self):
alist = doublelist.DoubleList()
head_node = doublelist.Node('head')
alist.insert_head(doublelist.Node('not head'))
alist.insert_head(head_node)
self.assertEqual(alist.nil.next, head_node)
self.assertNotEqual(alist.nil.prev, head_node)
self.assertEqual(alist.length, 2)
def test_clear(self):
alist = doublelist.DoubleList()
alist.insert_tail(doublelist.Node(1))
alist.insert_tail(doublelist.Node(2))
alist.insert_tail(doublelist.Node(3))
self.assertEqual(alist.count(), 3)
alist.clear()
self.assertEqual(alist.count(), 0)
def test_find_min(self):
alist = doublelist.DoubleList()
node = doublelist.Node(1)
alist.insert_tail(node)
alist.insert_tail(doublelist.Node(2))
alist.insert_tail(doublelist.Node(3))
alist.insert_tail(doublelist.Node(9))
alist.insert_tail(doublelist.Node(6))
self.assertEqual(alist.find_min(), node)
def test_remove_tail(self):
alist = doublelist.DoubleList()
node_to_remove = doublelist.Node('tail to remove')
alist.insert_tail(doublelist.Node('final tail'))
alist.insert_tail(node_to_remove)
length = alist.count()
removed_node = alist.remove_tail()
self.assertEqual(alist.nil.prev.data, 'final tail')
self.assertEqual(removed_node, node_to_remove)
self.assertEqual(alist.count(), length - 1)
def test_remove_head(self):
alist = doublelist.DoubleList()
node_to_remove = doublelist.Node('head to remove')
alist.insert_head(doublelist.Node('final head'))
alist.insert_head(node_to_remove)
length = alist.count()
removed_node = alist.remove_head()
self.assertEqual(alist.nil.next.data,
doublelist.Node('final head').data)
self.assertEqual(removed_node, node_to_remove)
self.assertEqual(alist.count(), length - 1)
def test_remove_the_last(self):
alist = doublelist.DoubleList()
node = doublelist.Node('to remove')
alist.insert_tail(doublelist.Node(1))
alist.insert_tail(doublelist.Node(2))
alist.insert_tail(doublelist.Node(3))
alist.insert_tail(doublelist.Node(4))
alist.insert_tail(node)
node_to_remove = alist.nil.next.next.next.next.next
self.assertEqual(alist.count(), 5)
alist.remove(node_to_remove)
self.assertNotEqual(alist.nil.next.next.next.next.next, node_to_remove)
self.assertEqual(alist.count(), 4)
def test_remove_tail_one_element_list(self):
alist = doublelist.DoubleList()
alist.insert_tail(doublelist.Node('the only one'))
self.assertTrue(alist.nil.next is alist.nil.prev
and alist.nil.next is not alist.nil)
alist.remove_tail()
self.assertTrue(alist.nil.next is alist.nil)
self.assertTrue(alist.nil.prev is alist.nil)
def test_is_empty(self):
self.assertTrue(doublelist.DoubleList().is_empty())
alist = doublelist.DoubleList()
alist.insert_head(doublelist.Node(10))
self.assertFalse(alist.is_empty())
def test_remove_from_empty_list(self):
alist = doublelist.DoubleList()
node = doublelist.Node(30)
with self.assertRaises(ValueError):
alist.remove(node)