def test_rotations():
"""Tests my rotations, balance, and depth with a simple AVLtree"""
# Initialization etc. should work fine, just inherits from well-tested BST
bintree = AVLTree()
assert bintree.depth() == 0
with pytest.raises(ValueError):
bintree._rotate_left()
bintree.insert(5)
assert bintree.depth() == 1
with pytest.raises(ValueError):
bintree._rotate_left()
with pytest.raises(ValueError):
bintree._rotate_right()
bintree.insert(3)
assert bintree.depth() == 2
with pytest.raises(ValueError):
bintree._rotate_right() # 3 is on left
bintree._rotate_left() # 3 now head
bintree._rotate_right() # 5 is head again
bintree.insert(7)
bintree.insert(6)
bintree.insert(2)
bintree.insert(4)
bintree.insert(1)
bintree.insert(9)
bintree.insert(10) # All in order, no rotations done
# 5
# / \
# 3 7
# /\ / \
# 2 4 6 9
# | |
# 1 10
bintree._rotate_right()
# 7
# / \
# 5 9
# | \ \
# 3 6 10
# /\
# 2 4
# |
# 1
assert bintree.value == 7
assert bintree.balance() == 2
assert bintree.size() == 9
assert bintree.depth() == 5
assert bintree.rightchild.value == 9
assert bintree.leftchild.value == 5
assert bintree.leftchild.rightchild.value == 6
bintree.leftchild._rotate_left()
# Note that this breaks stuff at head; the update of depth/_level is part
# of insert()/delete(), so 7 never gets releveled without the next line
bintree._relevel()
# 7
# / \
# 3 9
# | \ \
# 2 5 10
# / / \
# 1 4 6
assert bintree.balance() == 1
assert bintree.depth() == 4
pivot_node = bintree.leftchild
assert pivot_node.value == 3
assert pivot_node.leftchild.value == 2
assert pivot_node.rightchild.value == 5
