def test_threeelements(self):
"""Tests when there are three elements."""
root = Node(key=42)
left = Node(key=0, parent=root)
right = Node(key=50, parent=root)
root.left = left
root.right = right
self.assertEqual(findsuccessor(left), root)
self.assertEqual(findsuccessor(root), right)
self.assertEqual(findsuccessor(right), None)
def test_textbooktree(self):
"""Tests the tree provided by the textbook."""
A = Node(key=19)
B = Node(key=7, parent=A)
I = Node(key=43, parent=A)
A.left = B
A.right = I
C = Node(key=3, parent=B)
F = Node(key=11, parent=B)
B.left = C
B.right = F
D = Node(key=2, parent=C)
E = Node(key=5, parent=C)
C.left = D
C.right = E
G = Node(key=17, parent=F)
F.right = G
H = Node(key=13, parent=G)
G.left = H
J = Node(23, parent=I)
O = Node(47, parent=I)
I.left = J
I.right = O
K = Node(key=37, parent=J)
J.right = K
L = Node(key=29, parent=K)
N = Node(key=41, parent=K)
K.left = L
K.right = N
M = Node(key=31, parent=L)
L.right = M
P = Node(key=53, parent=O)
O.right = P
self.assertEqual(findsuccessor(P), None)
self.assertEqual(findsuccessor(G), A)
self.assertEqual(findsuccessor(A), J)
def test_singleelement(self):
"""Tests when there is only one element. No successor here."""
root = Node(key=42)
self.assertEqual(findsuccessor(root), None)
