def test_paybacks(collective_with_transfers_for_payback):
collective, user_1, user_2, user_3 = collective_with_transfers_for_payback
paybacks = calc_paybacks(collective)
assert len(paybacks) == 3
assert paybacks[0].debtor == user_3
assert paybacks[0].creditor == user_1
assert paybacks[0].amount == 48.33333333333333
assert paybacks[1].debtor == user_3
assert paybacks[1].creditor == user_2
assert paybacks[1].amount == 8.333333333333329
assert paybacks[2].debtor == user_1
assert paybacks[2].creditor == user_2
assert paybacks[2].amount == 50.0
# Adding a Liquidation can flip the creditor/debtor relation,
# as otherwise the balance would become negative.
mommy.make("purchases.Liquidation",
collective=collective,
creditor=user_1,
debtor=user_2,
amount=60.0)
paybacks = calc_paybacks(collective)
assert len(paybacks) == 3
assert paybacks[0].debtor == user_3
assert paybacks[0].creditor == user_1
assert paybacks[0].amount == 48.33333333333333
assert paybacks[1].debtor == user_3
assert paybacks[1].creditor == user_2
assert paybacks[1].amount == 8.333333333333329
assert paybacks[2].debtor == user_2
assert paybacks[2].creditor == user_1
assert paybacks[2].amount == 10.0
def test_calc_paybacks_with_negative_transfers(collective):
user_1 = mommy.make("auth.User", username="******")
user_2 = mommy.make("auth.User", username="******")
user_3 = mommy.make("auth.User", username="******")
collective.add_member(user_1)
collective.add_member(user_2)
collective.add_member(user_3)
mommy.make("purchases.Purchase",
collective=collective,
buyer=user_1,
name="Electricty Bill Refund",
price=-90.00)
mommy.make("purchases.Purchase",
collective=collective,
buyer=user_2,
name="Pizza",
price=15.00)
mommy.make("purchases.Liquidation",
collective=collective,
creditor=user_2,
debtor=user_3,
name="This makes no sense, but hey",
amount=-5.00)
paybacks = calc_paybacks(collective)
assert len(paybacks) == 3
data = [(payback.debtor, payback.creditor, payback.amount)
for payback in paybacks]
assert (user_1, user_2, 40.00) in data
assert (user_1, user_3, 25.00) in data
assert (user_2, user_3, 5.00) in data
def cashup(request, key):
collective = collective_from_key(key)
paybacks = [payback.to_json() for payback in calc_paybacks(collective)]
return Response(paybacks)
def stats(self):
"""Calculate financial status for each member of the Collective.
Returns:
{
'median_debt': 50.00,
'median_purchased': 15.95,
'overall_debt': 50.00,
'overall_purchased': 603.45,
'member_id_to_balance': {
'<member1-id>': -140.23,
'<member2-id>': 67.04,
...
},
'cashup': [
{'debtor': ..., 'creditor': ..., 'amount': ...},
...
],
}
"""
collective = self
members = collective.members
num_members = len(members)
purchases = collective.purchases
num_purchases = purchases.count()
liquidations = collective.liquidations
num_liquidations = liquidations.count()
prices = [float(purchase.price.amount) for purchase in purchases]
overall_purchased = sum(prices)
per_member = float(overall_purchased) / float(num_members)
debts = [
float(liquidation.amount.amount) for liquidation in liquidations
]
overall_debt = sum(debts)
median_purchased = 0
if prices:
median_purchased = median(prices)
median_debt = 0
if debts:
median_debt = median(debts)
member_id_to_balance = {}
for member in collective.members:
member_purchased = sum([
float(purchase.price.amount) for purchase in purchases
if purchase.buyer == member
])
credit = sum([
float(liq.amount.amount) for liq in liquidations
if liq.creditor == member
])
debt = sum([
float(liq.amount.amount) for liq in liquidations
if liq.debtor == member
])
has_to_pay = (per_member - float(member_purchased) -
float(credit) + float(debt))
balance = has_to_pay * -1
if balance == 0: # Remove '-' from the display.
balance = 0
member_id_to_balance[member.id] = balance
sorted_balances = sorted(member_id_to_balance.items(),
key=lambda item: item[1],
reverse=True)
serialized_paybacks = [
payback.to_json() for payback in calc_paybacks(collective)
]
stats = {
"median_debt": median_debt,
"median_purchased": median_purchased,
"num_liquidations": num_liquidations,
"num_purchases": num_purchases,
"overall_debt": overall_debt,
"overall_purchased": overall_purchased,
"sorted_balances": sorted_balances,
"cashup": serialized_paybacks,
}
return stats