feat: Add normalization for invalid multiselect values in Validable model

src/country_workspace/models/base.py

@@ -122,6 +122,18 @@ def update_checksum(self, update_fields: Iterable[str] | None) -> Iterable[str]
     def checker(self) -> "DataChecker":
         raise NotImplementedError
 
+    @staticmethod
+    def _normalize_invalid_value_for_field(field: Any, value: Any) -> Any:
+        if not getattr(getattr(field, "widget", None), "allow_multiple_selected", False):
+            return value
+        if value is None:
+            return []
+        if isinstance(value, list):
+            return value
+        if isinstance(value, tuple | set):
+            return list(value)
+        return [value]
+
     def validate_with_checker(self, fail_if_alien: bool = False) -> bool:
         update_fields = []
         errors = self.checker.validate([self.flex_fields], fail_if_alien=fail_if_alien)
@@ -138,7 +150,10 @@ def validate_with_checker(self, fail_if_alien: bool = False) -> bool:
             # keep invalid values
             for field_name in new_errors:
                 if field_name in flex_fields:
-                    self.flex_fields[field_name] = flex_fields[field_name]
+                    field = self.checker.form.fields.get(field_name)
+                    self.flex_fields[field_name] = self._normalize_invalid_value_for_field(
+                        field, flex_fields[field_name]
+                    )
             update_fields.append("flex_fields")
 
         self.last_checked = timezone.now()

tests/models/test_m_household.py

@@ -4,6 +4,8 @@
 
 import pytest
 
+from country_workspace.models.base import Validable
+
 if TYPE_CHECKING:
     from country_workspace.models import Household
     from country_workspace.workspaces.models import CountryHousehold, CountryIndividual
@@ -35,3 +37,71 @@ def test_validate_with_checker(individual: "CountryHousehold"):
     with mock.patch.object(household.program.beneficiary_validator, "validate", Mock(return_value=["Error"])):
         assert not household.validate_with_checker()
         assert household.errors == {"dct": ["Error"]}
+
+
+def test_validate_with_checker_preserves_multiselect_invalid_values_as_list(household):
+    checker = Mock()
+    checker.validate.return_value = {household.pk: {"reasons_oos": ["Invalid value"]}}
+    checker.form = Mock(
+        cleaned_data={},
+        fields={
+            "reasons_oos": Mock(widget=Mock(allow_multiple_selected=True)),
+        },
+    )
+    household.flex_fields = {"reasons_oos": "invalid-choice"}
+
+    with mock.patch.object(type(household), "checker", mock.PropertyMock(return_value=checker)):
+        household.validate_with_checker()
+
+    household.refresh_from_db()
+    assert household.flex_fields["reasons_oos"] == ["invalid-choice"]
+
+
+def test_normalize_invalid_value_for_field_passthrough_for_non_multiselect():
+    field = Mock(widget=Mock(allow_multiple_selected=False))
+
+    value = "raw-value"
+    result = Validable._normalize_invalid_value_for_field(field, value)
+
+    assert result == value
+
+
+def test_normalize_invalid_value_for_field_none_for_multiselect():
+    field = Mock(widget=Mock(allow_multiple_selected=True))
+
+    result = Validable._normalize_invalid_value_for_field(field, None)
+
+    assert result == []
+
+
+def test_normalize_invalid_value_for_field_list_for_multiselect():
+    field = Mock(widget=Mock(allow_multiple_selected=True))
+
+    value = ["a", "b"]
+    result = Validable._normalize_invalid_value_for_field(field, value)
+
+    assert result == value
+
+
+def test_normalize_invalid_value_for_field_tuple_for_multiselect():
+    field = Mock(widget=Mock(allow_multiple_selected=True))
+
+    result = Validable._normalize_invalid_value_for_field(field, ("a", "b"))
+
+    assert result == ["a", "b"]
+
+
+def test_normalize_invalid_value_for_field_set_for_multiselect():
+    field = Mock(widget=Mock(allow_multiple_selected=True))
+
+    result = Validable._normalize_invalid_value_for_field(field, {"a", "b"})
+
+    assert set(result) == {"a", "b"}
+
+
+def test_normalize_invalid_value_for_field_scalar_for_multiselect():
+    field = Mock(widget=Mock(allow_multiple_selected=True))
+
+    result = Validable._normalize_invalid_value_for_field(field, "single")
+
+    assert result == ["single"]