In test_decimal, convert heuristic for skipping tests into an explicit skiplist.

Lib/test/test_decimal.py

@@ -78,10 +78,41 @@ skip_expected = not os.path.isdir(directory)
 
 # list of individual .decTest test ids that correspond to tests that
 # we're skipping for one reason or another.
-skipped_test_ids = [
-    'scbx164',  # skipping apparently implementation-specific scaleb
-    'scbx165',  # tests, pending clarification of scaleb rules.
-]
+skipped_test_ids = set([
+    # Skip implementation-specific scaleb tests.
+    'scbx164',
+    'scbx165',
+
+    # For some operations (currently exp, ln, log10, power), the decNumber
+    # reference implementation imposes additional restrictions on the context
+    # and operands.  These restrictions are not part of the specification;
+    # however, the effect of these restrictions does show up in some of the
+    # testcases.  We skip testcases that violate these restrictions, since
+    # Decimal behaves differently from decNumber for these testcases so these
+    # testcases would otherwise fail.
+    'expx901',
+    'expx902',
+    'expx903',
+    'expx905',
+    'lnx901',
+    'lnx902',
+    'lnx903',
+    'lnx905',
+    'logx901',
+    'logx902',
+    'logx903',
+    'logx905',
+    'powx1183',
+    'powx1184',
+    'powx4001',
+    'powx4002',
+    'powx4003',
+    'powx4005',
+    'powx4008',
+    'powx4010',
+    'powx4012',
+    'powx4014',
+    ])
 
 # Make sure it actually raises errors when not expected and caught in flags
 # Slower, since it runs some things several times.
@@ -172,27 +203,6 @@ LOGICAL_FUNCTIONS = (
     'same_quantum',
     )
 
-# For some operations (currently exp, ln, log10, power), the decNumber
-# reference implementation imposes additional restrictions on the
-# context and operands.  These restrictions are not part of the
-# specification; however, the effect of these restrictions does show
-# up in some of the testcases.  We skip testcases that violate these
-# restrictions, since Decimal behaves differently from decNumber for
-# these testcases so these testcases would otherwise fail.
-
-decNumberRestricted = ('power', 'ln', 'log10', 'exp')
-DEC_MAX_MATH = 999999
-def outside_decNumber_bounds(v, context):
-    if (context.prec > DEC_MAX_MATH or
-        context.Emax > DEC_MAX_MATH or
-        -context.Emin > DEC_MAX_MATH):
-        return True
-    if not v._is_special and v and (
-        v.adjusted() > DEC_MAX_MATH or
-        v.adjusted() < 1-2*DEC_MAX_MATH):
-        return True
-    return False
-
 class DecimalTest(unittest.TestCase):
     """Class which tests the Decimal class against the test cases.
 
@@ -330,22 +340,6 @@ class DecimalTest(unittest.TestCase):
 
         ans = FixQuotes(ans)
 
-        # skip tests that are related to bounds imposed in the decNumber
-        # reference implementation
-        if fname in decNumberRestricted:
-            if fname == 'power':
-                if not (vals[1]._isinteger() and
-                        -1999999997 <= vals[1] <= 999999999):
-                    if outside_decNumber_bounds(vals[0], self.context) or \
-                            outside_decNumber_bounds(vals[1], self.context):
-                        #print "Skipping test %s" % s
-                        return
-            else:
-                if outside_decNumber_bounds(vals[0], self.context):
-                    #print "Skipping test %s" % s
-                    return
-
-
         if EXTENDEDERRORTEST and fname not in ('to_sci_string', 'to_eng_string'):
             for error in theirexceptions:
                 self.context.traps[error] = 1