Add case number pattern regression test

tests/test_case_number_pattern_contract.py

@@ -0,0 +1,10 @@
+import re
+
+from dutch_recognizers import CASE_NUMBER_VALUE_REGEX
+from test_cases.legal_regression_cases import CASE_NUMBER_EXAMPLES
+
+
+def test_known_case_number_shapes_match_core_case_number_regex():
+    pattern = re.compile(rf"^{CASE_NUMBER_VALUE_REGEX}$")
+    for value in CASE_NUMBER_EXAMPLES:
+        assert pattern.match(value), f"Case number shape should match: {value}"