def test_fibo_one():
assert fibo(1) == 1
def test_fibo_zero():
assert fibo(0) == 0
def test_fibo_400():
assert fibo(400) > 102334155
def test_fibo_minus():
assert fibo(-5) == 0
def test_fibo_18():
assert fibo(18) == 2584
def test_fibo_5():
assert fibo(5) == 5