Merge in release25-maint r60793:

 Added checks for integer overflows, contributed by Google. Some are
 only available if asserts are left in the code, in cases where they
 can't be triggered from Python code.
diff --git a/Lib/test/test_array.py b/Lib/test/test_array.py
index b11c9d6..34a8f79 100755
--- a/Lib/test/test_array.py
+++ b/Lib/test/test_array.py
@@ -1009,6 +1009,23 @@
 class DoubleTest(FPTest):
     typecode = 'd'
     minitemsize = 8
+
+    def test_alloc_overflow(self):
+        a = array.array('d', [-1]*65536)
+        try:
+            a *= 65536
+        except MemoryError:
+            pass
+        else:
+            self.fail("a *= 2**16 didn't raise MemoryError")
+        b = array.array('d', [ 2.71828183, 3.14159265, -1])
+        try:
+            b * 1431655766
+        except MemoryError:
+            pass
+        else:
+            self.fail("a * 1431655766 didn't raise MemoryError")
+
 tests.append(DoubleTest)
 
 def test_main(verbose=None):