def test_trc_calculates_correctly():
# arrange
demand = get_demand()
raw_costs = get_raw_costs()
order_quantity = 100
# act
trc = Costs.total_relevant_cost(raw_costs=raw_costs,
demand=demand,
order_quantity=order_quantity)
# assert
ordering_cost = Costs.ordering_cost(ordering_cost=raw_costs.ordering_cost,
demand_quantity=demand.quantity,
order_quantity=order_quantity)
holding_cost = Costs.holding_cost(holding_cost=raw_costs.holding_cost,
order_quantity=order_quantity)
assert trc == ordering_cost + holding_cost
def test_ordering_cost_calculates_correctly():
oc = Costs.ordering_cost(ordering_cost=100.0,
demand_quantity=250,
order_quantity=25)
assert oc == 100.0 * (250 / 25)
def test_ordering_cost_with_zero_order_quantity_raises():
with pytest.raises(ValueError):
Costs.ordering_cost(ordering_cost=1.0,
demand_quantity=1,
order_quantity=0)
def test_ordering_cost_with_negative_demand_quantity_raises():
with pytest.raises(ValueError):
Costs.ordering_cost(ordering_cost=1.0,
demand_quantity=-1,
order_quantity=1)
def test_ordering_cost_with_missing_demand_quantity_raises():
with pytest.raises(ValueError):
Costs.ordering_cost(ordering_cost=1.0,
demand_quantity=None,
order_quantity=1)
