def test_raises_exception():
with pytest.raises(TypeError):
sum_custom(1.0)
with pytest.raises(TypeError):
sum_custom("This is a string")
def test_negative():
assert sum_custom(-1) == -1
assert sum_custom(-10) == -1
def test_border_case():
assert sum_custom(1) == 1
assert sum_custom(0) == 0
assert sum_custom(-1) == -1
assert sum_custom(-2) == -1
def test_positive():
# partitioning n
assert sum_custom(2) == 0 + 1 + 2
assert sum_custom(3) == 0 + 1 + 2 + 3
assert sum_custom(5) == 15
assert sum_custom(10) == 55
