--- a/Lib/test/test_support.py	Wed Aug 09 14:56:33 2006 +0000
+++ b/Lib/test/test_support.py	Wed Aug 09 15:37:26 2006 +0000
@@ -314,6 +314,12 @@
 _1G = 1024 * _1M
 _2G = 2 * _1G
 
+# Hack to get at the maximum value an internal index can take.
+class _Dummy:
+    def __getslice__(self, i, j):
+        return j
+MAX_Py_ssize_t = _Dummy()[:]
+
 def set_memlimit(limit):
     import re
     global max_memuse
@@ -328,7 +334,9 @@
     if m is None:
         raise ValueError('Invalid memory limit %r' % (limit,))
     memlimit = int(float(m.group(1)) * sizes[m.group(3).lower()])
-    if memlimit < 2.5*_1G:
+    if memlimit > MAX_Py_ssize_t:
+        memlimit = MAX_Py_ssize_t
+    if memlimit < _2G - 1:
         raise ValueError('Memory limit %r too low to be useful' % (limit,))
     max_memuse = memlimit
 
@@ -371,6 +379,17 @@
         return wrapper
     return decorator
 
+def bigaddrspacetest(f):
+    """Decorator for tests that fill the address space."""
+    def wrapper(self):
+        if max_memuse < MAX_Py_ssize_t:
+            if verbose:
+                sys.stderr.write("Skipping %s because of memory "
+                                 "constraint\n" % (f.__name__,))
+        else:
+            return f(self)
+    return wrapper
+
 #=======================================================================
 # Preliminary PyUNIT integration.