tweak noop filter behavior, add tests for coverage

Author: bckohan

doc/source/changelog.rst

@@ -4,9 +4,10 @@
 Change Log
 ==========
 
-v2.2.0 (2025-03-23)
+v2.2.0 (2025-03-27)
 ===================
 
+* Implemented `Need a DRF integration for FlagFields <https://github.com/bckohan/django-enum/issues/113>`_
 * Fixed `FilterSet override of filter_for_lookup disregards meta options. <https://github.com/bckohan/django-enum/issues/111>`_
 * Implemented `Add EnumFlagFilter to support has_any and has_all flag queries. <https://github.com/bckohan/django-enum/issues/110>`_
 * Fixed `Enum types that resolve to primitives of str or int but that do not inherit from those types can result in validation errors. <https://github.com/bckohan/django-enum/issues/109>`_

src/django_enum/filters.py

@@ -147,13 +147,13 @@ def __init__(
         )
         self.lookup_expr = "has_all" if conjoined else "has_any"
 
+    def is_noop(self, qs, value):
+        return value is None or value == ""
+
     def filter(self, qs, value):
-        if value in {None, ""} or self.is_noop(qs, value):
+        if self.is_noop(qs, value):
             return qs
 
-        if value == self.null_value:
-            return self.get_method(qs)(Q(**{f"{self.field_name}__isnull": True}))
-
         # special case of no activate flags, performs an exact lookup
         # the form cleans unsupplied fields into 0s so we make sure this was supplied
         # before filtering on it

tests/test_requests.py

@@ -1307,6 +1307,38 @@ def list_to_objects(self, resp_content):
 
     if find_spec("django_filters"):  # pragma: no cover
 
+        def test_filter_misc_behavior(self):
+            from django_enum.filters import EnumFlagFilter
+
+            filter = EnumFlagFilter(enum=self.SmallPositiveFlagEnum)
+            qry = FlagFilterTester.objects
+            self.assertTrue(filter.is_noop(qry, None))
+            self.assertTrue(filter.is_noop(qry, ""))
+            self.assertFalse(
+                filter.is_noop(
+                    qry,
+                    [
+                        self.SmallPositiveFlagEnum.ONE,
+                        self.SmallPositiveFlagEnum.TWO,
+                        self.SmallPositiveFlagEnum.THREE,
+                        self.SmallPositiveFlagEnum.FOUR,
+                        self.SmallPositiveFlagEnum.FIVE,
+                    ],
+                )
+            )
+            self.assertFalse(
+                filter.is_noop(
+                    qry,
+                    self.SmallPositiveFlagEnum.ONE
+                    | self.SmallPositiveFlagEnum.TWO
+                    | self.SmallPositiveFlagEnum.THREE
+                    | self.SmallPositiveFlagEnum.FOUR
+                    | self.SmallPositiveFlagEnum.FIVE,
+                )
+            )
+            self.assertIs(qry, filter.filter(qry, None))
+            self.assertIs(qry, filter.filter(qry, ""))
+
         def test_django_filter_flags(self):
             self.do_test_django_filter(reverse(f"{self.NAMESPACE}:flag-filter"))