TST: add a test for non match

unittests/test_converters.py

@@ -584,7 +584,7 @@ def test_date_converter():
     assert matches["date"].year == 2022
 
     dictconverter = DateElementConverter(
-        definition={"match_value": "(?P<date>.*)",
+        definition={"match_value": r"(?P<date>(\d|-)+)",
                     "date_format": "%y-%m-%d"},
         name="conv",
         converter_registry=converter_registry)
@@ -592,3 +592,6 @@ def test_date_converter():
     assert "date" in matches
     assert isinstance(matches["date"], datetime.date)
     assert matches["date"].year == 2022
+
+    matches = dictconverter.match(TextElement("text", "alve"))
+    assert matches is None