The other half of Issue #1580: use short float repr where possible.
Addresses the float -> string conversion, using David Gay's code which
was added in Mark Dickinson's checkin r71663.
Also addresses these, which are intertwined with the short repr
changes:
- Issue #5772: format(1e100, '<') produces '1e+100', not '1.0e+100'
- Issue #5515: 'n' formatting with commas no longer works poorly
with leading zeros.
- PEP 378 Format Specifier for Thousands Separator: implemented
for floats.
diff --git a/Lib/test/test_float.py b/Lib/test/test_float.py
index 123a69d..8c250e8 100644
--- a/Lib/test/test_float.py
+++ b/Lib/test/test_float.py
@@ -1,6 +1,7 @@
import unittest, struct
import os
+import sys
from test import support
import math
from math import isinf, isnan, copysign, ldexp
@@ -10,6 +11,10 @@
INF = float("inf")
NAN = float("nan")
+#locate file with float format test values
+test_dir = os.path.dirname(__file__) or os.curdir
+format_testfile = os.path.join(test_dir, 'formatfloat_testcases.txt')
+
class GeneralFloatCases(unittest.TestCase):
def test_float(self):
@@ -24,6 +29,10 @@
self.assertRaises(ValueError, float, "+-3.14")
self.assertRaises(ValueError, float, "-+3.14")
self.assertRaises(ValueError, float, "--3.14")
+ self.assertRaises(ValueError, float, ".nan")
+ self.assertRaises(ValueError, float, "+.inf")
+ self.assertRaises(ValueError, float, ".")
+ self.assertRaises(ValueError, float, "-.")
self.assertEqual(float(b" \u0663.\u0661\u0664 ".decode('raw-unicode-escape')), 3.14)
@support.run_with_locale('LC_NUMERIC', 'fr_FR', 'de_DE')
@@ -316,6 +325,73 @@
self.assertEqual(v, eval(repr(v)))
floats_file.close()
+class FormatTestCase(unittest.TestCase):
+ @unittest.skipUnless(float.__getformat__("double").startswith("IEEE"),
+ "test requires IEEE 754 doubles")
+ def test_format_testfile(self):
+ for line in open(format_testfile):
+ if line.startswith('--'):
+ continue
+ line = line.strip()
+ if not line:
+ continue
+
+ lhs, rhs = map(str.strip, line.split('->'))
+ fmt, arg = lhs.split()
+ self.assertEqual(fmt % float(arg), rhs)
+ self.assertEqual(fmt % -float(arg), '-' + rhs)
+
+ @unittest.skipUnless(getattr(sys, 'float_repr_style', '') == 'short',
+ "applies only when using short float repr style")
+ def test_short_repr(self):
+ # test short float repr introduced in Python 3.1. One aspect
+ # of this repr is that we get some degree of str -> float ->
+ # str roundtripping. In particular, for any numeric string
+ # containing 15 or fewer significant digits, those exact same
+ # digits (modulo trailing zeros) should appear in the output.
+ # No more repr(0.03) -> "0.029999999999999999"!
+
+ test_strings = [
+ # output always includes *either* a decimal point and at
+ # least one digit after that point, or an exponent.
+ '0.0',
+ '1.0',
+ '0.01',
+ '0.02',
+ '0.03',
+ '0.04',
+ '0.05',
+ '1.23456789',
+ '10.0',
+ '100.0',
+ # values >= 1e16 get an exponent...
+ '1000000000000000.0',
+ '9999999999999990.0',
+ '1e+16',
+ '1e+17',
+ # ... and so do values < 1e-4
+ '0.001',
+ '0.001001',
+ '0.00010000000000001',
+ '0.0001',
+ '9.999999999999e-05',
+ '1e-05',
+ # values designed to provoke failure if the FPU rounding
+ # precision isn't set correctly
+ '8.72293771110361e+25',
+ '7.47005307342313e+26',
+ '2.86438000439698e+28',
+ '8.89142905246179e+28',
+ '3.08578087079232e+35',
+ ]
+
+ for s in test_strings:
+ negs = '-'+s
+ self.assertEqual(s, repr(float(s)))
+ self.assertEqual(negs, repr(float(negs)))
+
+
+
# Beginning with Python 2.6 float has cross platform compatible
# ways to create and represent inf and nan
class InfNanTest(unittest.TestCase):