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-rw-r--r--Lib/test/test_decimal.py25
1 files changed, 24 insertions, 1 deletions
diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py
index ea74f6c..1feaf2e 100644
--- a/Lib/test/test_decimal.py
+++ b/Lib/test/test_decimal.py
@@ -4722,9 +4722,33 @@ class PyWhitebox(unittest.TestCase):
c.prec = 1
x = Decimal("152587890625") ** Decimal('-0.5')
+ self.assertEqual(x, Decimal('3e-6'))
+ c.prec = 2
+ x = Decimal("152587890625") ** Decimal('-0.5')
+ self.assertEqual(x, Decimal('2.6e-6'))
+ c.prec = 3
+ x = Decimal("152587890625") ** Decimal('-0.5')
+ self.assertEqual(x, Decimal('2.56e-6'))
+ c.prec = 28
+ x = Decimal("152587890625") ** Decimal('-0.5')
+ self.assertEqual(x, Decimal('2.56e-6'))
+
c.prec = 201
x = Decimal(2**578) ** Decimal("-0.5")
+ # See https://github.com/python/cpython/issues/118027
+ # Testing for an exact power could appear to hang, in the Python
+ # version, as it attempted to compute 10**(MAX_EMAX + 1).
+ # Fixed via https://github.com/python/cpython/pull/118503.
+ c.prec = P.MAX_PREC
+ c.Emax = P.MAX_EMAX
+ c.Emin = P.MIN_EMIN
+ c.traps[P.Inexact] = 1
+ D2 = Decimal(2)
+ # If the bug is still present, the next statement won't complete.
+ res = D2 ** 117
+ self.assertEqual(res, 1 << 117)
+
def test_py_immutability_operations(self):
# Do operations and check that it didn't change internal objects.
Decimal = P.Decimal
@@ -5737,7 +5761,6 @@ class CWhitebox(unittest.TestCase):
with C.localcontext(rounding=C.ROUND_DOWN):
self.assertEqual(format(y, '#.1f'), '6.0')
-
@requires_docstrings
@requires_cdecimal
class SignatureTest(unittest.TestCase):