update value

test_main.py

@@ -8,7 +8,7 @@ class TestCalculator(unittest.TestCase):
         self.assertEqual(add(-1, 1), 0)
 
     def test_subtract(self):
-        self.assertEqual(subtract(5, 2), 3)
+        self.assertEqual(subtract(5, 2), 2)
         self.assertEqual(subtract(0, 1), -1)