Add __format__ method to Decimal, to support PEP 3101

This commit is contained in:
Mark Dickinson 2008-02-29 02:16:37 +00:00
parent b4cbc98c39
commit 1ddf1d8482
3 changed files with 335 additions and 0 deletions

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@ -615,6 +615,98 @@ class DecimalImplicitConstructionTest(unittest.TestCase):
self.assertEqual(eval('Decimal(10)' + sym + 'E()'),
'10' + rop + 'str')
class DecimalFormatTest(unittest.TestCase):
'''Unit tests for the format function.'''
def test_formatting(self):
# triples giving a format, a Decimal, and the expected result
test_values = [
('e', '0E-15', '0e-15'),
('e', '2.3E-15', '2.3e-15'),
('e', '2.30E+2', '2.30e+2'), # preserve significant zeros
('e', '2.30000E-15', '2.30000e-15'),
('e', '1.23456789123456789e40', '1.23456789123456789e+40'),
('e', '1.5', '1.5e+0'),
('e', '0.15', '1.5e-1'),
('e', '0.015', '1.5e-2'),
('e', '0.0000000000015', '1.5e-12'),
('e', '15.0', '1.50e+1'),
('e', '-15', '-1.5e+1'),
('e', '0', '0e+0'),
('e', '0E1', '0e+1'),
('e', '0.0', '0e-1'),
('e', '0.00', '0e-2'),
('.6e', '0E-15', '0.000000e-9'),
('.6e', '0', '0.000000e+6'),
('.6e', '9.999999', '9.999999e+0'),
('.6e', '9.9999999', '1.000000e+1'),
('.6e', '-1.23e5', '-1.230000e+5'),
('.6e', '1.23456789e-3', '1.234568e-3'),
('f', '0', '0'),
('f', '0.0', '0.0'),
('f', '0E-2', '0.00'),
('f', '0.00E-8', '0.0000000000'),
('f', '0E1', '0'), # loses exponent information
('f', '3.2E1', '32'),
('f', '3.2E2', '320'),
('f', '3.20E2', '320'),
('f', '3.200E2', '320.0'),
('f', '3.2E-6', '0.0000032'),
('.6f', '0E-15', '0.000000'), # all zeros treated equally
('.6f', '0E1', '0.000000'),
('.6f', '0', '0.000000'),
('.0f', '0', '0'), # no decimal point
('.0f', '0e-2', '0'),
('.0f', '3.14159265', '3'),
('.1f', '3.14159265', '3.1'),
('.4f', '3.14159265', '3.1416'),
('.6f', '3.14159265', '3.141593'),
('.7f', '3.14159265', '3.1415926'), # round-half-even!
('.8f', '3.14159265', '3.14159265'),
('.9f', '3.14159265', '3.141592650'),
('g', '0', '0'),
('g', '0.0', '0.0'),
('g', '0E1', '0e+1'),
('G', '0E1', '0E+1'),
('g', '0E-5', '0.00000'),
('g', '0E-6', '0.000000'),
('g', '0E-7', '0e-7'),
('g', '-0E2', '-0e+2'),
('.0g', '3.14159265', '3'), # 0 sig fig -> 1 sig fig
('.1g', '3.14159265', '3'),
('.2g', '3.14159265', '3.1'),
('.5g', '3.14159265', '3.1416'),
('.7g', '3.14159265', '3.141593'),
('.8g', '3.14159265', '3.1415926'), # round-half-even!
('.9g', '3.14159265', '3.14159265'),
('.10g', '3.14159265', '3.14159265'), # don't pad
('%', '0E1', '0%'),
('%', '0E0', '0%'),
('%', '0E-1', '0%'),
('%', '0E-2', '0%'),
('%', '0E-3', '0.0%'),
('%', '0E-4', '0.00%'),
('.3%', '0', '0.000%'), # all zeros treated equally
('.3%', '0E10', '0.000%'),
('.3%', '0E-10', '0.000%'),
('.3%', '2.34', '234.000%'),
('.3%', '1.234567', '123.457%'),
('.0%', '1.23', '123%'),
('e', 'NaN', 'NaN'),
('f', '-NaN123', '-NaN123'),
('+g', 'NaN456', '+NaN456'),
('.3e', 'Inf', 'Infinity'),
('.16f', '-Inf', '-Infinity'),
('.0g', '-sNaN', '-sNaN'),
('', '1.00', '1.00'),
]
for fmt, d, result in test_values:
self.assertEqual(format(Decimal(d), fmt), result)
class DecimalArithmeticOperatorsTest(unittest.TestCase):
'''Unit tests for all arithmetic operators, binary and unary.'''
@ -1363,6 +1455,7 @@ def test_main(arith=False, verbose=None, todo_tests=None, debug=None):
DecimalExplicitConstructionTest,
DecimalImplicitConstructionTest,
DecimalArithmeticOperatorsTest,
DecimalFormatTest,
DecimalUseOfContextTest,
DecimalUsabilityTest,
DecimalPythonAPItests,