def test_expected_present_value__raises_InvalidEPVInputs_when_ndim_greater_than_2(
life_table, ):
n = 100
probabilities = life_table.get_pxs()[:n]
cash_flows = np.array([[tuple([1] * n), tuple([1] * n), tuple([1] * n)]])
interest_rates = tuple([0.07] * n)
try:
expected_present_value(cash_flows, probabilities, interest_rates)
assert False
except InvalidEPVInputs:
assert True
def test_expected_present_value__raises_InvalidEPVInputs_when_lengths_do_not_match(
life_table, ):
n = 100
probabilities = life_table.get_pxs()[:n]
cash_flows = tuple([1] * (n + 1))
interest_rates = tuple([0.07] * n)
try:
expected_present_value(cash_flows, probabilities, interest_rates)
assert False
except InvalidEPVInputs:
assert True
def test_expected_present_value__array(life_table):
n = 100
probabilities = np.array(life_table.get_pxs()[:n])
cash_flows = np.array(tuple([1] * n))
interest_rates = np.array(tuple([0.07] * n))
epv = expected_present_value(cash_flows, probabilities, interest_rates)
expected = life_table.axn(0, 0.07, n)
percent_error = abs(((expected - epv) / expected) * 100)
assert percent_error < 1.5
def test_expected_present_value__n_is_3(life_table):
n = 3
probabilities = life_table.get_pxs()[:n]
cash_flows = tuple([1] * n)
interest_rates = tuple([0.07] * n)
epv = expected_present_value(cash_flows, probabilities, interest_rates)
expected = life_table.axn(0, 0.07, n)
percent_error = abs(((expected - epv) / expected) * 100)
assert percent_error < 0.5
def test_expected_present_value__matrix(life_table):
n = 100
probabilities = np.array([
life_table.get_pxs()[:n],
life_table.get_pxs()[:n],
life_table.get_pxs()[:n]
])
cash_flows = np.array([tuple([1] * n), tuple([1] * n), tuple([1] * n)])
interest_rates = np.array(
[tuple([0.07] * n),
tuple([0.06] * n),
tuple([0.05] * n)])
epv = expected_present_value(cash_flows, probabilities, interest_rates)
expecteds = np.array([
life_table.axn(0, 0.07, n),
life_table.axn(0, 0.06, n),
life_table.axn(0, 0.05, n),
])
for i, expected in enumerate(expecteds):
percent_error = abs(((expected - epv[i]) / expected) * 100)
assert percent_error < 3