diff --git a/test/test_callinfo.py b/test/test_callinfo.py
index 8500188..024cfe9 100644
--- a/test/test_callinfo.py
+++ b/test/test_callinfo.py
@@ -268,11 +268,11 @@ class Test_callinfo_methods:
     def test_dismantle_callsign_with_cyrillic_characters(self, fix_callinfo):
 
         with pytest.raises(KeyError):
-            fix_callinfo._dismantle_callsign("RД3MAS") #cyrillic letter 'Д' in call
+            fix_callinfo._dismantle_callsign(u"RД3MAS") #cyrillic letter 'Д' in call
         with pytest.raises(KeyError):
-            fix_callinfo._dismantle_callsign("RД3/K9MAS") #cyrillic letter 'Д' in prefix
+            fix_callinfo._dismantle_callsign(u"RД3/K9MAS") #cyrillic letter 'Д' in prefix
         with pytest.raises(KeyError):
-            fix_callinfo._dismantle_callsign("R2EA/М") #cyrillic letter 'M' in appendix
+            fix_callinfo._dismantle_callsign(u"R2EA/М") #cyrillic letter 'M' in appendix
 
     def test_dismantle_callsign_with_VK9_special_suffixes(self, fix_callinfo):