diff --git a/Lib/test/test_struct.py b/Lib/test/test_struct.py
index 684dc6c..6032895 100644
--- a/Lib/test/test_struct.py
+++ b/Lib/test/test_struct.py
@@ -511,6 +511,13 @@
             for c in [b'\x01', b'\x7f', b'\xff', b'\x0f', b'\xf0']:
                 self.assertTrue(struct.unpack('>?', c)[0])
 
+    def test_count_overflow(self):
+        hugecount = '{}b'.format(sys.maxsize+1)
+        self.assertRaises(struct.error, struct.calcsize, hugecount)
+
+        hugecount2 = '{}b{}H'.format(sys.maxsize//2, sys.maxsize//2)
+        self.assertRaises(struct.error, struct.calcsize, hugecount2)
+
     if IS32BIT:
         def test_crasher(self):
             self.assertRaises(MemoryError, struct.pack, "357913941b", "a")