fix for issue 3862: test_array fails FreeBSD 7 amd64

FreeBSD 7's underlying malloc() is behaves differently to earlier versions
and seriously overcommits available memory on amd64.  This may affect
other 64bit platforms in some circumstances, so the scale of the
problematic test is wound back.

Patch by Mark Dickinson, reviewed by Martin von Loewis.

diff --git a/Lib/test/test_array.py b/Lib/test/test_array.py
index 34a8f79ce8556c5ea6a71c655bb53841438b07f0..2efbc7d6772f8aeb590b5b23e893834cd2e6672b 100755 (executable)
--- a/Lib/test/test_array.py
+++ b/Lib/test/test_array.py
@@ -1011,20 +1011,21 @@ class DoubleTest(FPTest):
     minitemsize = 8
 
     def test_alloc_overflow(self):
+        from sys import maxsize
         a = array.array('d', [-1]*65536)
         try:
-            a *= 65536
+            a *= maxsize//65536 + 1
         except MemoryError:
             pass
         else:
-            self.fail("a *= 2**16 didn't raise MemoryError")
+            self.fail("Array of size > maxsize created - MemoryError expected")
         b = array.array('d', [ 2.71828183, 3.14159265, -1])
         try:
-            b * 1431655766
+            b * (maxsize//3 + 1)
         except MemoryError:
             pass
         else:
-            self.fail("a * 1431655766 didn't raise MemoryError")
+            self.fail("Array of size > maxsize created - MemoryError expected")
 
 tests.append(DoubleTest)