def test_calculate_interests_delta_time_out_of_bounds():
with pytest.raises(ValueError):
calculate_interests(
balance=1000000000,
internal_interest_rate=1000,
delta_time_in_seconds=DELTA_TIME_MINIMAL_ALLOWED_VALUE - 1,
)
def test_interests_calculation_returns_integer():
assert isinstance(
calculate_interests(
balance=1000,
internal_interest_rate=100,
delta_time_in_seconds=SECONDS_PER_YEAR,
),
int,
)
def test_get_interests_paid_during_opening_of_trustline(
ethindex_db_for_currency_network_with_trustlines_and_interests,
currency_network_with_trustlines_and_interests_session,
web3,
chain,
accounts,
wait_for_ethindex_to_sync,
):
"""Test that opening a trustline with balance and interests will allow us to get resulting paid interests"""
currency_network = currency_network_with_trustlines_and_interests_session
initial_transfer = -100
interest_rate = 2000
currency_network.close_trustline(accounts[1], accounts[2])
currency_network.update_trustline_with_accept(
accounts[1],
accounts[2],
12345,
12345,
interest_rate,
1000,
False,
initial_transfer,
)
path = [accounts[0], accounts[1], accounts[2], accounts[3]]
timestamp = web3.eth.getBlock("latest").timestamp
timestamp += ONE_YEAR_IN_SECONDS + 1
chain.time_travel(timestamp)
currency_network.transfer(path[0], 9, 1000, path, b"")
wait_for_ethindex_to_sync()
accrued_interests = EventsInformationFetcher(
ethindex_db_for_currency_network_with_trustlines_and_interests
).get_list_of_paid_interests_for_trustline(currency_network.address,
accounts[2], accounts[1])
assert len(accrued_interests) == 1
assert accrued_interests[0].value == calculate_interests(
initial_transfer, interest_rate, ONE_YEAR_IN_SECONDS)
assert accrued_interests[0].interest_rate == interest_rate
assert accrued_interests[0].timestamp == web3.eth.getBlock(
"latest").timestamp
def get_accrued_interests_from_events(balance_update_events,
trustline_update_events):
accrued_interests = []
for (pre_balance_event,
post_balance_event) in toolz.itertoolz.sliding_window(
2, balance_update_events):
balance = balance_viewed_from_user(pre_balance_event)
interest_rate = get_interests_rates_of_trustline_for_user_before_timestamp(
trustline_update_events, balance, post_balance_event.timestamp)
interest_value = calculate_interests(
balance,
interest_rate,
post_balance_event.timestamp - pre_balance_event.timestamp,
)
accrued_interests.append(
InterestAccrued(interest_value, interest_rate,
post_balance_event.timestamp))
return accrued_interests
def test_interests_calculation_negative_balance():
assert (calculate_interests(
balance=-1000,
internal_interest_rate=100,
delta_time_in_seconds=SECONDS_PER_YEAR,
) == -10)
def tests_interests_calculation_no_time():
assert (calculate_interests(balance=1000,
internal_interest_rate=100,
delta_time_in_seconds=0) == 0)
def test_interests_calculation_gives_same_result_as_smart_contracts():
assert (calculate_interests(
balance=1000000000000000000,
internal_interest_rate=2000,
delta_time_in_seconds=SECONDS_PER_YEAR,
) == 221402758160169828) # taken from contract calculation
def test_interests_calculation_high_interest_rate():
assert calculate_interests(
balance=1000000000000000000,
internal_interest_rate=2000,
delta_time_in_seconds=SECONDS_PER_YEAR,
) == pytest.approx(1000000000000000000 * (math.exp(0.20) - 1), rel=0.01)
def test_interests_calculation_zero_interest_rate():
assert (calculate_interests(
balance=1000,
internal_interest_rate=0,
delta_time_in_seconds=SECONDS_PER_YEAR,
) == 0)
def test_calculate_interests_time_glitch(small_non_positive_delta_time):
calculate_interests(
balance=1000000000,
internal_interest_rate=1000,
delta_time_in_seconds=small_non_positive_delta_time,
) == 0
