reapply of r57378 to fix bug 1725856
diff --git a/Lib/test/test_bsddb.py b/Lib/test/test_bsddb.py
index 2da4045..dfee3dc 100755
--- a/Lib/test/test_bsddb.py
+++ b/Lib/test/test_bsddb.py
@@ -131,6 +131,22 @@
             items.append(self.f.previous())
         self.assertSetEquals(items, self.d.items())
 
+    def test_first_while_deleting(self):
+        # Test for bug 1725856
+        self.assert_(len(self.d) >= 2, "test requires >=2 items")
+        for _ in self.d:
+            key = self.f.first()[0]
+            del self.f[key]
+        self.assertEqual(0, len(self.f), "expected empty db after test")
+
+    def test_last_while_deleting(self):
+        # Test for bug 1725856's evil twin
+        self.assert_(len(self.d) >= 2, "test requires >=2 items")
+        for _ in self.d:
+            key = self.f.last()[0]
+            del self.f[key]
+        self.assertEqual(0, len(self.f), "expected empty db after test")
+
     def test_set_location(self):
         self.assertEqual(self.f.set_location('e'), ('e', self.d['e']))