Extend tests to cover KeyError exceptions.

Author: acolomb

test/test_pdo.py

@@ -70,6 +70,10 @@ def test_pdo_getitem(self):
         self.assertIs(node.tpdo[0x2002], by_object_index)
         self.assertIs(node.pdo[0x1600][0x2002], by_object_index)
 
+        self.assertRaises(KeyError, lambda: node.pdo[0])
+        self.assertRaises(KeyError, lambda: node.tpdo[0])
+        self.assertRaises(KeyError, lambda: node.pdo['DOES NOT EXIST'])
+
     def test_pdo_save(self):
         self.node.tpdo.save()
         self.node.rpdo.save()