diff --git a/test.py b/test.py
index f57c65e..46f87c0 100644
--- a/test.py
+++ b/test.py
@@ -23,9 +23,9 @@ class TestManaCostMath(unittest.TestCase):
         self.assertEquals(0, result.mana['R'])
         self.assertEquals(1, result.mana['W'])
     def test_subtract_manacost_from_mana_insufficient_addtl(self):
-        self.assertRaises(Exception, lambda: Mana('RRW'), ManaCost('3R'))
+        self.assertRaises(Exception, lambda: Mana('RRW') - ManaCost('3R'))
     def test_subtract_manacost_from_mana_insufficient_color(self):
-        self.assertRaises(Exception, lambda: Mana('RRW'), ManaCost('2U'))
+        self.assertRaises(Exception, lambda: Mana('RRW') - ManaCost('2U'))
 
 if __name__ == '__main__':
-    unittest.main()
\ No newline at end of file
+    unittest.main()