NPO-Accounting/oxrlib Changeset - b270db02e8d7

Changeset - b270db02e8d7

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Brett Smith - 7 years ago 2017-06-29 20:54:16
brettcsmith@brettcsmith.org

historical: Ledger conversions show enough rate precision to stay balanced.

3 files changed with 36 insertions and 9 deletions:

oxrlib/commands/historical.py

tests/historical1.json

tests/test_historical.py

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oxrlib/commands/historical.py

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@@ ... / @@ -25,12 +25,16 @@ class Formatter: @@
         if code in self.signed_currencies:
             fmt = '¤' + fmt
         else:
             fmt = fmt + ' ¤¤'
         return babel.numbers.format_currency(amount, code, fmt, currency_digits=currency_digits)
     def currency_decimal(self, amount, currency):
         amt_s = babel.numbers.format_currency(amount, currency, '###0.###')
         return decimal.Decimal(amt_s)
     def format_rate(self, rate):
         return "{:g}".format(rate)
     def format_rate_pair(self, from_curr, to_curr):
         from_amt = 1
         to_amt = self.rate.convert(from_amt, from_curr, to_curr)
@@ ... / @@ -58,32 +62,36 @@ class LedgerFormatter(Formatter): @@
     def __init__(self, rate, signed_currencies=(), base_fmt='#,##0.###',
                  rate_precision=5, denomination=None):
         super().__init__(rate, signed_currencies, base_fmt)
         self.rate_prec = rate_precision
         self.denomination = denomination
     def normalize_rate(self, rate):
     def normalize_rate(self, rate, prec=None):
         if prec is None:
             prec = self.rate_prec
         _, digits, exponent = rate.normalize().as_tuple()
         # Return ``self.rate_prec`` nonzero digits of precision, if available.
         prec = self.rate_prec - min(0, exponent + len(digits))
         # Return ``prec`` nonzero digits of precision, if available.
         prec -= min(0, exponent + len(digits))
         quant_to = '1.{}'.format('0' * prec)
         try:
             qrate = rate.quantize(decimal.Decimal(quant_to))
         except decimal.InvalidOperation:
             # The original rate doesn't have that much precision, so use it raw.
             qrate = rate
         return qrate.normalize()
     def format_rate(self, rate):
         return str(self.normalize_rate(rate))
     def format_ledger_rate(self, rate, curr):
         nrate = self.normalize_rate(rate)
         rate_s = self.format_currency(nrate, curr, currency_digits=False)
     def format_ledger_rate_raw(self, rate, curr):
         rate_s = self.format_currency(rate, curr, currency_digits=False)
         return "{{={0}}} @ {0}".format(rate_s)
     def format_ledger_rate(self, rate, curr):
         return self.format_ledger_rate_raw(self.normalize_rate(rate), curr)
     def format_rate_pair(self, from_curr, to_curr):
         from_amt = 1
         to_amt = self.rate.convert(from_amt, from_curr, to_curr)
         return "{} {} {}".format(
             from_amt, from_curr, self.format_ledger_rate(to_amt, to_curr))
@@ ... / @@ -97,15 +105,20 @@ class LedgerFormatter(Formatter): @@
     def format_denominated_rate(self, amount, currency, default_denomination):
         denomination = self._denomination_for(currency, default_denomination)
         amt_s = self.format_currency(amount, currency)
         if denomination is None:
             return amt_s
         else:
             rate = self.rate.convert(1, currency, denomination)
             return "{} {}".format(amt_s, self.format_ledger_rate(rate, denomination))
         full_rate = self.rate.convert(1, currency, denomination)
         to_amt = self.currency_decimal(amount * full_rate, denomination)
         for prec in itertools.count(self.rate_prec):
             rate = self.normalize_rate(full_rate, prec)
             got_amt = self.currency_decimal(amount * rate, denomination)
             if (got_amt == to_amt) or (rate == full_rate):
                 break
         return "{} {}".format(amt_s, self.format_ledger_rate_raw(rate, denomination))
     def format_conversion(self, from_amt, from_curr, to_curr):
         to_amt = self.rate.convert(from_amt, from_curr, to_curr)
         return "{}\n{}".format(
             self.format_denominated_rate(from_amt, from_curr, to_curr),
             self.format_denominated_rate(to_amt, to_curr, None),

tests/historical1.json

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@@ ... / @@ -4,9 +4,10 @@ @@
     "timestamp": 982342800,
     "base": "USD",
     "rates": {
         "AED": 3.67246,
         "ALL": 144.529793,
         "ANG": 1.79,
         "RUB": 57.0763,
         "USD": 1
+    }
+}

tests/test_historical.py

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@@ ... / @@ -143,6 +143,19 @@ def test_from_denomination(historical1_responder, output): @@
                           to_currency='ALL', amount=10,
                           ledger=True, denomination='USD')
     lines = lines_from_run(config, output)
     assert next(lines) == '$10.00\n'
     assert next(lines) == '1,445 ALL {=$0.006919} @ $0.006919\n'
     assert next(lines, None) is None
 def test_rate_precision_added_as_needed(historical1_responder, output):
     config = build_config(historical1_responder, from_currency='RUB',
                           to_currency='USD', amount=63805,
                           ledger=True, denomination='USD')
     lines = lines_from_run(config, output)
     # 63,805 / 57.0763 (the RUB rate) == $1,117.89
     # But using the truncated rate: 63,805 * .01752 == $1,117.86
     # Make sure the rate is specified with enough precision to get the
     # correct conversion amount.
     assert next(lines) == '63,805.00 RUB {=$0.0175204} @ $0.0175204\n'
     assert next(lines) == '$1,117.89\n'
     assert next(lines, None) is None

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