reports: Balance is initialized with just amounts.

This works fine with how we're currently using it, makes transformation
methods easier to implement, and avoids potential bugs where a balance is
initialized with a bad mapping.

conservancy_beancount/reports/core.py

@@ -60,27 +60,22 @@ class Balance(Mapping[str, data.Amount]):
     """
     __slots__ = ('_currency_map',)
 
-    def __init__(self,
+    def __init__(self, source: Iterable[data.Amount]=()) -> None:
-                 source: Union[Iterable[Tuple[str, data.Amount]],
+        self._currency_map = {amount.currency: amount for amount in source}
-                               Mapping[str, data.Amount]]=(),
-    ) -> None:
-        if isinstance(source, Mapping):
-            source = source.items()
-        self._currency_map = {
-            currency: amount.number for currency, amount in source
-        }
 
     def _add_amount(self,
-                    currency_map: MutableMapping[str, Decimal],
+                    currency_map: MutableMapping[str, data.Amount],
                     amount: data.Amount,
     ) -> None:
+        code = amount.currency
         try:
-            currency_map[amount.currency] += amount.number
+            current_number = currency_map[code].number
         except KeyError:
-            currency_map[amount.currency] = amount.number
+            current_number = Decimal(0)
+        currency_map[code] = data.Amount(current_number + amount.number, code)
 
     def _add_other(self,
-                   currency_map: MutableMapping[str, Decimal],
+                   currency_map: MutableMapping[str, data.Amount],
                    other: Union[data.Amount, 'Balance'],
     ) -> None:
         if isinstance(other, Balance):
@@ -90,21 +85,19 @@ class Balance(Mapping[str, data.Amount]):
             self._add_amount(currency_map, other)
 
     def __repr__(self) -> str:
-        return f"{type(self).__name__}({self._currency_map!r})"
+        values = [repr(amt) for amt in self.values()]
+        return f"{type(self).__name__}({values!r})"
 
     def __str__(self) -> str:
         return self.format()
 
-    def __abs__(self) -> 'Balance':
+    def __abs__(self: BalanceType) -> BalanceType:
-        return type(self)(
+        return type(self)(bc_amount.abs(amt) for amt in self.values())
-            (key, bc_amount.abs(amt)) for key, amt in self.items()
-        )
 
     def __add__(self: BalanceType, other: Union[data.Amount, 'Balance']) -> BalanceType:
         retval_map = self._currency_map.copy()
         self._add_other(retval_map, other)
-        return type(self)((code, data.Amount(number, code))
+        return type(self)(retval_map.values())
-                          for code, number in retval_map.items())
 
     def __eq__(self, other: Any) -> bool:
         if (self.is_zero()
@@ -114,13 +107,11 @@ class Balance(Mapping[str, data.Amount]):
         else:
             return super().__eq__(other)
 
-    def __neg__(self) -> 'Balance':
+    def __neg__(self: BalanceType) -> BalanceType:
-        return type(self)(
+        return type(self)(-amt for amt in self.values())
-            (key, -amt) for key, amt in self.items()
-        )
 
     def __getitem__(self, key: str) -> data.Amount:
-        return data.Amount(self._currency_map[key], key)
+        return self._currency_map[key]
 
     def __iter__(self) -> Iterator[str]:
         return iter(self._currency_map)
@@ -132,7 +123,7 @@ class Balance(Mapping[str, data.Amount]):
                      op_func: Callable[[DecimalCompat, DecimalCompat], bool],
                      operand: DecimalCompat,
     ) -> bool:
-        return all(op_func(number, operand) for number in self._currency_map.values())
+        return all(op_func(amt.number, operand) for amt in self.values())
 
     def eq_zero(self) -> bool:
         """Returns true if all amounts in the balance == 0."""

tests/test_reports_balance.py

@@ -34,6 +34,10 @@ DEFAULT_STRINGS = [
     ({'JPY': '-5500.00', 'BRL': '-8500.00'}, "-8,500.00 BRL, -5,500 JPY"),
 ]
 
+def amounts_from_map(currency_map):
+    for code, number in currency_map.items():
+        yield testutil.Amount(number, code)
+
 def test_empty_balance():
     balance = core.Balance()
     assert not balance
@@ -49,7 +53,7 @@ def test_empty_balance():
 ])
 def test_zero_balance(currencies):
     keys = currencies.split()
-    balance = core.Balance(testutil.balance_map((key, 0) for key in keys))
+    balance = core.Balance(testutil.Amount(0, key) for key in keys)
     assert balance
     assert len(balance) == len(keys)
     assert balance.is_zero()
@@ -62,22 +66,22 @@ def test_zero_balance(currencies):
     'JPY INR BRL',
 ])
 def test_nonzero_balance(currencies):
-    amounts = testutil.balance_map(zip(currencies.split(), itertools.count(110, 100)))
+    amounts = dict(zip(currencies.split(), itertools.count(110, 100)))
-    balance = core.Balance(amounts.items())
+    balance = core.Balance(amounts_from_map(amounts))
     assert balance
     assert len(balance) == len(amounts)
     assert not balance.is_zero()
-    assert all(balance[key] == amt for key, amt in amounts.items())
+    assert all(balance[key] == testutil.Amount(amt, key) for key, amt in amounts.items())
 
 def test_mixed_balance():
-    amounts = testutil.balance_map(USD=0, EUR=120)
+    amounts = {'USD': 0, 'EUR': 120}
-    balance = core.Balance(amounts.items())
+    balance = core.Balance(amounts_from_map(amounts))
     assert balance
     assert len(balance) == 2
     assert not balance.is_zero()
-    assert all(balance[key] == amt for key, amt in amounts.items())
+    assert all(balance[key] == testutil.Amount(amt, key) for key, amt in amounts.items())
 
-@pytest.mark.parametrize('balance_map_kwargs,expected', [
+@pytest.mark.parametrize('mapping,expected', [
     ({}, True),
     ({'USD': 0}, True),
     ({'USD': 0, 'EUR': 0}, True),
@@ -89,13 +93,12 @@ def test_mixed_balance():
     ({'JPY': 10, 'BRL': 0}, False),
     ({'JPY': 10, 'BRL': 20}, False),
 ])
-def test_eq_zero(balance_map_kwargs, expected):
+def test_eq_zero(mapping, expected):
-    amounts = testutil.balance_map(**balance_map_kwargs)
+    balance = core.Balance(amounts_from_map(mapping))
-    balance = core.Balance(amounts.items())
     assert balance.eq_zero() == expected
     assert balance.is_zero() == expected
 
-@pytest.mark.parametrize('balance_map_kwargs,expected', [
+@pytest.mark.parametrize('mapping,expected', [
     ({}, True),
     ({'USD': 0}, True),
     ({'USD': 0, 'EUR': 0}, True),
@@ -106,12 +109,11 @@ def test_eq_zero(balance_map_kwargs, expected):
     ({'JPY': 10, 'BRL': 0}, True),
     ({'JPY': 10, 'BRL': 20}, True),
 ])
-def test_ge_zero(balance_map_kwargs, expected):
+def test_ge_zero(mapping, expected):
-    amounts = testutil.balance_map(**balance_map_kwargs)
+    balance = core.Balance(amounts_from_map(mapping))
-    balance = core.Balance(amounts.items())
     assert balance.ge_zero() == expected
 
-@pytest.mark.parametrize('balance_map_kwargs,expected', [
+@pytest.mark.parametrize('mapping,expected', [
     ({}, True),
     ({'USD': 0}, True),
     ({'USD': 0, 'EUR': 0}, True),
@@ -122,12 +124,11 @@ def test_ge_zero(balance_map_kwargs, expected):
     ({'JPY': 10, 'BRL': 0}, False),
     ({'JPY': 10, 'BRL': 20}, False),
 ])
-def test_le_zero(balance_map_kwargs, expected):
+def test_le_zero(mapping, expected):
-    amounts = testutil.balance_map(**balance_map_kwargs)
+    balance = core.Balance(amounts_from_map(mapping))
-    balance = core.Balance(amounts.items())
     assert balance.le_zero() == expected
 
-@pytest.mark.parametrize('balance_map_kwargs', [
+@pytest.mark.parametrize('mapping', [
     {},
     {'USD': 0},
     {'EUR': 10},
@@ -136,17 +137,13 @@ def test_le_zero(balance_map_kwargs, expected):
     {'JPY': -25, 'BRL': -35},
     {'JPY': 40, 'USD': 0, 'EUR': -50},
 ])
-def test_abs(balance_map_kwargs):
+def test_abs(mapping):
-    amounts = testutil.balance_map(**balance_map_kwargs)
+    actual = abs(core.Balance(amounts_from_map(mapping)))
-    actual = abs(core.Balance(amounts.items()))
+    assert set(actual) == set(mapping)
-    assert set(actual) == set(balance_map_kwargs)
+    for key, number in mapping.items():
-    abs_amounts = testutil.balance_map(**{
+        assert actual[key] == testutil.Amount(abs(number), key)
-        key: abs(number) for key, number in balance_map_kwargs.items()
-    })
-    for key in balance_map_kwargs:
-        assert actual[key] == abs_amounts[key]
 
-@pytest.mark.parametrize('balance_map_kwargs', [
+@pytest.mark.parametrize('mapping', [
     {},
     {'USD': 0},
     {'EUR': 10},
@@ -155,14 +152,13 @@ def test_abs(balance_map_kwargs):
     {'JPY': -25, 'BRL': -35},
     {'JPY': 40, 'USD': 0, 'EUR': -50},
 ])
-def test_neg(balance_map_kwargs):
+def test_neg(mapping):
-    amounts = testutil.balance_map(**balance_map_kwargs)
+    actual = -core.Balance(amounts_from_map(mapping))
-    actual = -core.Balance(amounts.items())
+    assert set(actual) == set(mapping)
-    assert set(actual) == set(balance_map_kwargs)
+    for key, number in mapping.items():
-    for key in balance_map_kwargs:
+        assert actual[key] == testutil.Amount(-number, key)
-        assert actual[key] == -amounts[key]
 
-@pytest.mark.parametrize('kwargs1,kwargs2,expected', [
+@pytest.mark.parametrize('map1,map2,expected', [
     ({}, {}, True),
     ({}, {'USD': 0}, True),
     ({}, {'EUR': 1}, False),
@@ -173,9 +169,9 @@ def test_neg(balance_map_kwargs):
     ({'USD': 1, 'EUR': 2, 'BRL': '3.0'}, {'USD': '1.0', 'EUR': '2.0'}, False),
     ({'USD': 1, 'EUR': 2}, {'USD': '1.0', 'EUR': '2.0'}, True),
 ])
-def test_eq(kwargs1, kwargs2, expected):
+def test_eq(map1, map2, expected):
-    bal1 = core.Balance(testutil.balance_map(**kwargs1))
+    bal1 = core.Balance(amounts_from_map(map1))
-    bal2 = core.Balance(testutil.balance_map(**kwargs2))
+    bal2 = core.Balance(amounts_from_map(map2))
     actual = bal1 == bal2
     assert actual == expected
 
@@ -186,8 +182,8 @@ def test_eq(kwargs1, kwargs2, expected):
     (-4000, 'BRL'),
 })
 def test_add_amount(number, currency):
-    start_amounts = testutil.balance_map(USD=500)
+    start_amount = testutil.Amount(500, 'USD')
-    start_bal = core.Balance(start_amounts)
+    start_bal = core.Balance([start_amount])
     add_amount = testutil.Amount(number, currency)
     actual = start_bal + add_amount
     if currency == 'USD':
@@ -195,9 +191,9 @@ def test_add_amount(number, currency):
         assert actual['USD'] == testutil.Amount(500 + number)
     else:
         assert len(actual) == 2
-        assert actual['USD'] == testutil.Amount(500)
+        assert actual['USD'] == start_amount
         assert actual[currency] == add_amount
-    assert start_bal == start_amounts
+    assert start_bal == {'USD': start_amount}
 
 @pytest.mark.parametrize('number,currency', {
     (50, 'USD'),
@@ -206,8 +202,7 @@ def test_add_amount(number, currency):
     (-4000, 'BRL'),
 })
 def test_iadd_amount(number, currency):
-    start_amounts = testutil.balance_map(USD=500)
+    balance = core.MutableBalance([testutil.Amount(500, 'USD')])
-    balance = core.MutableBalance(start_amounts)
     add_amount = testutil.Amount(number, currency)
     balance += add_amount
     if currency == 'USD':
@@ -218,7 +213,7 @@ def test_iadd_amount(number, currency):
         assert balance['USD'] == testutil.Amount(500)
         assert balance[currency] == add_amount
 
-@pytest.mark.parametrize('balance_map_kwargs', [
+@pytest.mark.parametrize('mapping', [
     {},
     {'USD': 0},
     {'EUR': 10},
@@ -227,18 +222,17 @@ def test_iadd_amount(number, currency):
     {'JPY': -25, 'BRL': -35},
     {'JPY': 40, 'USD': 0, 'EUR': -50},
 ])
-def test_add_balance(balance_map_kwargs):
+def test_add_balance(mapping):
-    start_numbers = {'USD': 500, 'BRL': 40000}
+    expect_numbers = {'USD': 500, 'BRL': 40000}
-    start_bal = core.Balance(testutil.balance_map(**start_numbers))
+    start_bal = core.Balance(amounts_from_map(expect_numbers))
-    expect_numbers = start_numbers.copy()
+    for code, number in mapping.items():
-    for code, number in balance_map_kwargs.items():
         expect_numbers[code] = expect_numbers.get(code, 0) + number
-    add_bal = core.Balance(testutil.balance_map(**balance_map_kwargs))
+    add_bal = core.Balance(amounts_from_map(mapping))
     actual = start_bal + add_bal
-    expected = core.Balance(testutil.balance_map(**expect_numbers))
+    expected = core.Balance(amounts_from_map(expect_numbers))
     assert actual == expected
 
-@pytest.mark.parametrize('balance_map_kwargs', [
+@pytest.mark.parametrize('mapping', [
     {},
     {'USD': 0},
     {'EUR': 10},
@@ -247,25 +241,24 @@ def test_add_balance(balance_map_kwargs):
     {'JPY': -25, 'BRL': -35},
     {'JPY': 40, 'USD': 0, 'EUR': -50},
 ])
-def test_iadd_balance(balance_map_kwargs):
+def test_iadd_balance(mapping):
-    start_numbers = {'USD': 500, 'BRL': 40000}
+    expect_numbers = {'USD': 500, 'BRL': 40000}
-    balance = core.MutableBalance(testutil.balance_map(**start_numbers))
+    balance = core.MutableBalance(amounts_from_map(expect_numbers))
-    expect_numbers = start_numbers.copy()
+    for code, number in mapping.items():
-    for code, number in balance_map_kwargs.items():
         expect_numbers[code] = expect_numbers.get(code, 0) + number
-    balance += core.Balance(testutil.balance_map(**balance_map_kwargs))
+    balance += core.Balance(amounts_from_map(mapping))
-    expected = core.Balance(testutil.balance_map(**expect_numbers))
+    expected = core.Balance(amounts_from_map(expect_numbers))
     assert balance == expected
 
-@pytest.mark.parametrize('balance_map_kwargs,expected', DEFAULT_STRINGS)
+@pytest.mark.parametrize('mapping,expected', DEFAULT_STRINGS)
-def test_str(balance_map_kwargs, expected):
+def test_str(mapping, expected):
-    amounts = testutil.balance_map(**balance_map_kwargs)
+    balance = core.Balance(amounts_from_map(mapping))
-    assert str(core.Balance(amounts.items())) == expected
+    assert str(balance) == expected
 
-@pytest.mark.parametrize('bal_kwargs,expected', DEFAULT_STRINGS)
+@pytest.mark.parametrize('mapping,expected', DEFAULT_STRINGS)
-def test_format_defaults(bal_kwargs, expected):
+def test_format_defaults(mapping, expected):
-    amounts = testutil.balance_map(**bal_kwargs)
+    balance = core.Balance(amounts_from_map(mapping))
-    assert core.Balance(amounts).format() == expected
+    assert balance.format() == expected
 
 @pytest.mark.parametrize('fmt,expected', [
     ('¤##0.0', '¥5000, -€1500.00'),
@@ -274,7 +267,7 @@ def test_format_defaults(bal_kwargs, expected):
     ('#,#00.0 ¤¤;(#,#00.0 ¤¤)', '5,000 JPY, (1,500.00 EUR)'),
 ])
 def test_format_fmt(fmt, expected):
-    amounts = testutil.balance_map(JPY=5000, EUR=-1500)
+    amounts = [testutil.Amount(5000, 'JPY'), testutil.Amount(-1500, 'EUR')]
     balance = core.Balance(amounts)
     assert balance.format(fmt) == expected
 
@@ -284,16 +277,15 @@ def test_format_fmt(fmt, expected):
     '\0',
 ])
 def test_format_sep(sep):
-    bal_kwargs, expected = DEFAULT_STRINGS[-1]
+    mapping, expected = DEFAULT_STRINGS[-1]
     expected = expected.replace(', ', sep)
-    amounts = testutil.balance_map(**bal_kwargs)
+    balance = core.Balance(amounts_from_map(mapping))
-    balance = core.Balance(amounts)
     assert balance.format(sep=sep) == expected
 
 def test_format_none():
-    amounts = testutil.balance_map(BRL=65000)
+    args = (65000, 'BRL')
-    balance = core.Balance(amounts)
+    balance = core.Balance([testutil.Amount(*args)])
-    expected = babel.numbers.format_currency(65000, 'BRL')
+    expected = babel.numbers.format_currency(*args)
     assert balance.format(None) == expected
 
 @pytest.mark.parametrize('empty', [

tests/test_reports_related_postings.py

@@ -90,7 +90,7 @@ def test_balance_credit_card(credit_card_cycle, index, expected):
     related = core.RelatedPostings(
         txn.postings[0] for txn in credit_card_cycle[:index + 1]
     )
-    assert related.balance() == testutil.balance_map(USD=expected)
+    assert related.balance() == {'USD': testutil.Amount(expected, 'USD')}
 
 def check_iter_with_balance(entries):
     expect_posts = [txn.postings[0] for txn in entries]
@@ -99,7 +99,8 @@ def check_iter_with_balance(entries):
     for post in expect_posts:
         number, currency = post.units
         balance_tally[currency] += number
-        expect_balances.append(testutil.balance_map(balance_tally.items()))
+        expect_balances.append({code: testutil.Amount(number, code)
+                                for code, number in balance_tally.items()})
     related = core.RelatedPostings(expect_posts)
     for (post, balance), exp_post, exp_balance in zip(
             related.iter_with_balance(),

tests/testutil.py

@@ -156,18 +156,6 @@ OPENING_EQUITY_ACCOUNTS = itertools.cycle([
     'Equity:OpeningBalance',
 ])
 
-def balance_map(source=None, **kwargs):
-    # The source and/or kwargs should map currency name strings to
-    # things you can pass to Decimal (a decimal string, an int, etc.)
-    # This returns a dict that maps currency name strings to Amount instances.
-    retval = {}
-    if source is not None:
-        retval.update((currency, Amount(number, currency))
-                      for currency, number in source)
-    if kwargs:
-        retval.update(balance_map(kwargs.items()))
-    return retval
-
 def OpeningBalance(acct=None, **txn_meta):
     if acct is None:
         acct = next(OPENING_EQUITY_ACCOUNTS)