Add tests for min max functions

Author: gazpachoking

tests/test_future/test_min_max.py

@@ -0,0 +1,25 @@
+# -*- coding: utf-8 -*-
+"""
+Tests for the min and max functions with `default` keyword.
+"""
+
+from __future__ import absolute_import, unicode_literals, print_function
+from future.builtins import *
+from future.tests.base import unittest
+
+
+class TestMinMax(unittest.TestCase):
+    def test_default(self):
+        self.assertEqual(min([], default=3), 3)
+        self.assertEqual(max([], default=3), 3)
+
+    def test_generator(self):
+        """
+        Issue #510
+        """
+        self.assertEqual(max((x for x in [3, 2, 1])), 3)
+        self.assertEqual(min((x for x in [1, 2, 3])), 1)
+
+    def test_empty_generator(self):
+        with self.assertRaises(ValueError):
+            min(x for x in [])