diff --git a/test/test_str2tokens.py b/test/test_str2tokens.py
index 25aa0e9..89a872f 100644
--- a/test/test_str2tokens.py
+++ b/test/test_str2tokens.py
@@ -43,6 +43,22 @@ class TestStr2tokens(unittest.TestCase):
         tok = str2in_tokens(exp)
         self.assertEqual(tok, ["(", -3, ")", "*","(", 2, ")" ])
 
+    def test_str2tokens_poly(self):
+        exp = "2x + 4"
+        post = str2in_tokens(exp)
+        self.assertEqual(post, [2, < Polynom [0, 1]>, '*', 4, '+'])
+
+
+    def test_str2tokens_poly_double_x(self):
+        exp = "xx + 4"
+        post = str2in_tokens(exp)
+        self.assertEqual(post, [< Polynom [0, 1]>, < Polynom [0, 1]>, '*', 4, '+'])
+
+    def test_str2tokens_poly(self):
+        exp = "x(2+1) + 4"
+        post = str2in_tokens(exp)
+        self.assertEqual(post, [< Polynom [0, 1]>, 2, 1, '+', '*', 4, '+'])
+
     def test_str2in_tokens_time_lack2(self):
         exp = "-3(2)"
         tok = str2in_tokens(exp)