Add test for creating tuple out of sys.version_info

Author: msimacek

graalpython/com.oracle.graal.python.test/src/tests/test_tuple.py

@@ -2,10 +2,12 @@
 # Copyright (C) 1996-2017 Python Software Foundation
 #
 # Licensed under the PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
+import sys
+
 import seq_tests
-#import pickle
 from compare import CompareTest
 
+
 class TupleTest(seq_tests.CommonTest):
 
     type2test = tuple
@@ -22,6 +24,9 @@ def test_constructors(self):
         self.assertEqual(tuple(''), ())
         self.assertEqual(tuple('spam'), ('s', 'p', 'a', 'm'))
 
+    def test_from_subclass(self):
+        self.assertIs(type(tuple(sys.version_info)), tuple)
+
     def test_literal(self):
         self.assertEqual((1,2,3), (*[1,2,3],))