def test_fib1():
# test edge 1
obs = fib(1)
assert obs == 1
def test_fib0():
# test edge 0
obs = fib(0)
assert obs == 1
def test_negative():
obs = fib(-1)
exp = NotImplemented
assert obs == exp
def test_fib6():
# test internal point
obs = fib(6)
assert obs == 8
def test_ints():
obs = fib(1.0)
exp = NotImplemented
assert obs == exp