def test_remove():
sklist = Skiplist()
sklist.add(1)
sklist.add(2)
assert sklist.remove(1) == True
assert sklist.remove(1) == False
assert sklist.remove(2) == True
def test_find():
sklist = Skiplist()
sklist.add(1)
sklist.add(2)
sklist.add(3)
assert sklist.find(1) == 1
assert sklist.find(0) == 1
assert sklist.find(2) == 2
assert sklist.find(10) == None
assert sklist.find(1.5) == 2
assert sklist.find(3) == 3
def test_find_predecessor():
sklist = Skiplist()
sklist.add(1)
sklist.add(2)
sklist.add(3)
sklist.add(4)
sklist.add(5)
assert sklist.find_predecessor(6)[0].data == 5
assert sklist.find_predecessor(4.5)[0].data == 4
assert sklist.find_predecessor(2.9)[0].data == 2
assert sklist.find_predecessor(1.1)[0].data == 1
assert sklist.find_predecessor(0.9)[0] == None
def test_add():
sklist = Skiplist()
assert sklist.add(10) == True
assert sklist.add(20) == True
assert sklist.add(10) == False
def test_find_predecessor():
sklist = Skiplist()
sklist.add(1)
sklist.add(2)
sklist.add(3)