refactor(forms-runtime): centralize owner-specific email normalization

Release v0.1.22. Coordinated integrity review: GovOPlaN/govoplan-core#298.

tests/test_email_normalization.py

@@ -0,0 +1,37 @@
+import unittest
+
+from govoplan_forms_runtime.backend.dsar_provider import _normalized_email
+from govoplan_forms_runtime.backend.email_normalization import normalize_status_email
+from govoplan_forms_runtime.backend.status_access import _normalize_email
+
+
+class EmailNormalizationTests(unittest.TestCase):
+    def test_status_access_and_dsar_share_the_same_selector_policy(self) -> None:
+        self.assertIs(normalize_status_email, _normalize_email)
+        self.assertIs(normalize_status_email, _normalized_email)
+
+    def test_existing_selector_results_remain_exact_at_policy_boundaries(self) -> None:
+        boundary = "a" * 308 + "@example.org"
+        values = (
+            (None, None), (False, None), (0, None), ("", None), ("   ", None),
+            (" Subject@Example.ORG ", "subject@example.org"),
+            ("\u00a0Straße@BÜRO.Example\u00a0", "strasse@büro.example"),
+            ("a+b@sub.example.org", "a+b@sub.example.org"),
+            ("a..b@example..org", "a..b@example..org"),  # Existing policy, not a new RFC validator.
+            ("a b@example.org", None), ("a@exa\tmple.org", None), ("a@exa\u00a0mple.org", None),
+            ("a@@example.org", None), ("@example.org", None), ("a@example", None),
+            ("a@.example.org", None), ("a@example.org.", None),
+            (boundary, boundary), ("a" + boundary, None),
+        )
+        for value, expected in values:
+            with self.subTest(value=value):
+                self.assertEqual(expected, normalize_status_email(value))
+
+    def test_selector_canonicalization_does_not_mutate_submitted_values(self) -> None:
+        values = {"email": " Subject@Example.ORG ", "other": ["001", "  ", None]}
+        self.assertEqual("subject@example.org", normalize_status_email(values["email"]))
+        self.assertEqual({"email": " Subject@Example.ORG ", "other": ["001", "  ", None]}, values)
+
+
+if __name__ == "__main__":
+    unittest.main()