def test_rebalance():
"""Tests my rebalancing algorithm"""
bintree = BST()
for i in xrange(100):
bintree.insert(random.randint(0, 1e6))
assert bintree.size() == 100
original_depth = bintree.depth()
bintree.rebalance()
assert abs(bintree.balance()) < 2
assert original_depth > bintree.depth()
bintree = BST()
for i in xrange(100):
bintree.insert(i) # Horribly unbalanced
assert bintree.size() == 100
assert bintree.depth() == 100
assert bintree.balance() == -99
bintree.rebalance()
assert abs(bintree.balance()) < 2
assert bintree.depth() < 10 # Much better, anyway
def test_balance():
aBST = BST()
assert aBST.balance() == 0
for num, bal in zip([4, 2, 6, 3, 7, 8, 9, 10, 11],
[0, 1, 0, 1, 0, -1, -2, -3]):
aBST.insert(num)
assert aBST.balance() == bal
def test_balance():
tree = BST()
assert tree.balance() == 0
items = [0, -2, -1, -4, -3]
for item in items:
tree.insert(item)
assert tree.balance() == 3
items = [1, 2, 3, 4]
for item in items:
tree.insert(item)
assert tree.balance() == -1
def test_balance():
"""balance(self) should return a positive or negative integer that
represents how well balanced the tree is. Trees deeper on the left return a
positive value, trees deeper on the right return a negative value.
An ideally-balanced tree should return 0."""
bintree = BST()
with pytest.raises(TypeError):
bintree.balance(1) # No values allowed
assert bintree.balance() == 0 # Empty tree
bintree.insert(5)
# 5
assert bintree.balance() == 0 # no children, it's balanced
bintree.insert(3)
# 5
# /
# 3
assert bintree.balance() == 1 # Deeper on the left
bintree.insert(7)
# 5
# / \
# 3 7
assert bintree.balance() == 0
bintree.insert(2)
bintree.insert(4)
# 5
# / \
# 3 7
# /\
# 2 4
assert bintree.balance() == 1 # Deeper on the left
bintree.insert(1)
# 5
# / \
# 3 7
# /\
# 2 4
# |
# 1
assert bintree.balance() == 2
bintree.insert(9)
bintree.insert(10)
# 5
# / \
# 3 7
# /\ \
# 2 4 9
# | |
# 1 10
assert bintree.balance() == 0
bintree.insert(12)
assert bintree.balance() == -1
def test_balance():
b = BST()
b.insert(10)
b.insert(5)
b.insert(15)
b.insert(3)
b.insert(2)
b.insert(1)
assert b._depth == 5
assert b._size == 6
assert b.balance(b._root) == -3
assert b.balance(b._root._left) == -3
assert b.balance(b._root._right) == -0
def test_left_balance():
bst = BST()
bst.insert(5)
bst.insert(4)
bst.insert(3)
bst.insert(6)
assert bst.balance() == 1
def test_right_balance():
bst = BST()
bst.insert(5)
bst.insert(6)
bst.insert(7)
bst.insert(3)
assert bst.balance() == -1
def test_left_balance():
bst = BST()
bst.insert(5)
bst.insert(4)
bst.insert(3)
bst.insert(6)
assert bst.balance() == 1
def test_right_balance():
bst = BST()
bst.insert(5)
bst.insert(6)
bst.insert(7)
bst.insert(3)
assert bst.balance() == -1
def test_make_balanced_randomly():
aBST = BST()
for y in range(300):
for x in range(1000):
aBST.insert(randint(0, 1000))
aBST.make_balanced()
b = aBST.balance()
assert b in [1, 0, -1]
def test_balance_left_super_heavy():
'''Test balance is positive if left is much greater than right depth.'''
bst = BST()
bst.insert(100)
bst.insert(90)
bst.insert(88)
bst.insert(70)
assert bst.balance() == 3
def test_right_rotate():
'''checks right_rotate balances the BTS'''
bst = BST()
bst.insert(20)
bst.insert(10)
bst.insert(5)
balance = bst.balance()
assert balance == 0
def test_delete_one_child():
"""delete(self, val) should remove val from the tree if present,
if not present it should do nothing. Return None in all cases"""
bintree = BST()
bintree.insert(5)
bintree.insert(3)
bintree.insert(7)
bintree.insert(2)
bintree.insert(4)
bintree.insert(1)
bintree.insert(9)
bintree.insert(10)
# 5
# / \
# 3 7
# /\ \
# 2 4 9
# | |
# 1 10
assert bintree.size() == 8
assert bintree.delete(7) is None
# 5
# / \
# 3 9
# /\ \
# 2 4 10
# |
# 1
assert bintree.size() == 7
assert not bintree.contains(7)
assert bintree.contains(9)
assert bintree.contains(10)
assert bintree.balance() == 1
assert bintree.delete(2) is None
# 5
# / \
# 3 9
# /\ \
# 1 4 10
assert bintree.size() == 6
assert not bintree.contains(2)
assert bintree.contains(1)
assert bintree.leftchild.leftchild.value == 1
assert bintree.balance() == 0
def test_delete_two_children():
bintree = BST()
bintree.insert(5)
bintree.insert(3)
bintree.insert(7)
bintree.insert(6)
bintree.insert(2)
bintree.insert(4)
bintree.insert(1)
bintree.insert(9)
bintree.insert(10)
# 5
# / \
# 3 7
# /\ / \
# 2 4 6 9
# | |
# 1 10
assert bintree.size() == 9
assert bintree.leftchild.balance() == 1 # The subtree at 3 is left-heavy
assert bintree.delete(3) is None # So this will delete left-style
# 5
# / \
# 2 7
# /\ / \
# 1 4 6 9
# |
# 10
assert bintree.size() == 8
assert bintree.leftchild.value == 2
assert bintree.balance() == -1 # The whole tree is now right-heavy
assert bintree.delete(5) is None # So deleting the top will go right-style
# 6
# / \
# 2 7
# /\ \
# 1 4 9
# |
# 10
assert bintree.value == 6
assert bintree.size() == 7
assert bintree.rightchild.value == 7
assert bintree.balance() == -1
def test_balane_returns_negative_number_if_left_branch_is_lower():
"""Test that balance returns a negative number when left side of tree is higher."""
from bst import BST
t = BST([9, 8, 7, 4, 6, 5, 1, 10, 14, 11])
assert t.balance() == -2
def test_balance_root_only():
'''Test balance is 0 if bst only has root.'''
bst = BST()
bst.insert(5)
assert bst.balance() == 0
def test_balance_empty_bst():
'''Test balance is 0 if bst is empty.'''
bst = BST()
assert bst.balance() == 0
def test_balance_is_even():
"""Test for balance of 0."""
a = BST([5, 4, 6, 3, 7, 2, 8])
assert a.balance() == 0
def test_balance_is_negative():
"""Test negative balance."""
a = BST([5, 4, 3, 2, 1, 6])
assert a.balance() == -3
def test_balance_1_node():
"""Test balance of tree of only head."""
from bst import BST
new_bst = BST()
new_bst.insert(10)
assert new_bst.balance() == 0
def test_balance_empty_tree():
"""Test balance of empty tree."""
from bst import BST
new_bst = BST()
assert new_bst.balance() == 0
def test_balance_returns_positive_number_if_right_branch_is_lower():
"""Test that balance returns a positive number when right side is higher."""
from bst import BST
t = BST([9, 8, 5, 14, 25, 15, 29])
assert t.balance() == 1
def test_balance_returns_string_if_bst_is_empty():
"""Test that balance returns 'tree is empty' if bst is empty."""
from bst import BST
t = BST()
assert t.balance() == 'Tree is empty.'