def test_termial_function_error(self, n: int) -> None:
"""Test termial function."""
with pytest.raises(ValueError):
State._termial_function(n)
def test_termial_function_solution(self, n: int) -> None:
"""Test solution to termial function."""
x = State._termial_function(n)
assert State._termial_function_solution(
x - 1) <= n <= State._termial_function_solution(x)
def test_termial_function_compute(self, n: int) -> None:
"""Test termial function - compute explicitly results."""
x = State._termial_function(n)
assert x == sum(range(n + 1))