From f1fe3142fbc44a568b460cf6bb660b0e92d0890a Mon Sep 17 00:00:00 2001
From: Pavel Savchenko <asfaltboy@gmail.com>
Date: Sun, 9 Oct 2022 07:40:59 +0100
Subject: [PATCH] fix: use True value for isnull operator

---
 advanced_filters/forms.py            |  2 +-
 advanced_filters/tests/test_forms.py | 44 +++++++++++++++++-----------
 2 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/advanced_filters/forms.py b/advanced_filters/forms.py
index 0ffe761..bd4406b 100644
--- a/advanced_filters/forms.py
+++ b/advanced_filters/forms.py
@@ -88,7 +88,7 @@ def _build_query_dict(self, formdata=None):
             formdata = self.cleaned_data
         key = "{field}__{operator}".format(**formdata)
         if formdata['operator'] == "isnull":
-            return {key: None}
+            return {key: True}
         elif formdata['operator'] == "istrue":
             return {formdata['field']: True}
         elif formdata['operator'] == "isfalse":
diff --git a/advanced_filters/tests/test_forms.py b/advanced_filters/tests/test_forms.py
index 4445e76..0fe67bc 100644
--- a/advanced_filters/tests/test_forms.py
+++ b/advanced_filters/tests/test_forms.py
@@ -71,23 +71,6 @@ def test_build_field_choices(self):
             'fname': 'First name'
         }
 
-    def test_build_query_dict(self):
-        data = self.data.copy()
-        form = AdvancedFilterQueryForm(self.fields, data=data)
-        assert form._build_query_dict() == {'fname__iexact': 'john'}
-
-        data['operator'] = 'isnull'
-        form = AdvancedFilterQueryForm(self.fields, data=data)
-        assert form._build_query_dict() == {'fname__isnull': None}
-
-        data['operator'] = 'istrue'
-        form = AdvancedFilterQueryForm(self.fields, data=data)
-        assert form._build_query_dict() == {'fname': True}
-
-        data['operator'] = 'isfalse'
-        form = AdvancedFilterQueryForm(self.fields, data=data)
-        assert form._build_query_dict() == {'fname': False}
-
     def test_make_query(self):
         form = AdvancedFilterQueryForm(self.fields, data=self.data)
         assert form.is_valid()
@@ -201,6 +184,33 @@ def test_all_operators_are_restored(self):
             assert res == expected[i]
 
 
+@pytest.mark.parametrize("fields, data, expected", [
+    (
+        dict(bday='birthday', fname='first name'),
+        dict(field='fname', value='john', operator='iexact'),
+        {'fname__iexact': 'john'}
+    ),
+    (
+        dict(bday='birthday', fname='first name'),
+        dict(field='fname', value='john', operator='isnull'),
+        {'fname__isnull': True}
+    ),
+    (
+        dict(bday='birthday', fname='first name'),
+        dict(field='fname', value='john', operator='istrue'),
+        {'fname': True}
+    ),
+    (
+        dict(bday='birthday', fname='first name'),
+        dict(field='fname', value='john', operator='isfalse'),
+        {'fname': False}
+    ),
+])
+def test_build_query_dict(data, fields, expected):
+    form = AdvancedFilterQueryForm(fields, data=data)
+    assert form._build_query_dict() == expected
+
+
 class CommonFormTest(TestCase):
     mgmg_form_data = {
         'form-TOTAL_FORMS': 1,