diff --git a/tests/test_jasinta.py b/tests/test_jasinta.py
--- a/tests/test_jasinta.py
+++ b/tests/test_jasinta.py
@@ -1,22 +1,18 @@
 from unittest import TestCase
-from unittest.mock import MagicMock
+from unittest.mock import patch
 
 from pyjsparser import parse
 
 from jasinta import interpret
-import std as jasinta_std
 
 
 class TestBasicAddition(TestCase):
-	def setUp(self):
-		self.mock_print = MagicMock()
-		jasinta_std.lib["document"]["write"] = self.mock_print
-
-	def test_interpret(self):
+	@patch("builtins.print")
+	def test_interpret(self, mock_print):
 		s = """var a=3;
 var b=1;
 var c=a+b;
 document.write(c);"""
 
 		interpret(parse(s))
-		self.mock_print.assert_called_with(4.0)
+		mock_print.assert_called_with(4)