Refs #24227 -- Replaced M2M isinstance checks by field.many_to_many

Thanks Markus Holtermann, Collin Anderson and Tim Graham for the reviews.

4 files changed, 11 insertions, 12 deletions

diff --git a/tests/admin_checks/tests.py b/tests/admin_checks/tests.py
index 2cf7f66d9d..c584cd42c9 100644
--- a/tests/admin_checks/tests.py
+++ b/tests/admin_checks/tests.py
@@ -583,7 +583,7 @@ class SystemChecksTestCase(SimpleTestCase):
         errors = BookAdmin(Book, AdminSite()).check()
         expected = [
             checks.Error(
-                "The value of 'fields' cannot include the ManyToManyField 'authors', "
+                "The value of 'fields' cannot include the many-to-many field 'authors' "
                 "because that field manually specifies a relationship model.",
                 obj=BookAdmin,
                 id='admin.E013',
@@ -601,8 +601,8 @@ class SystemChecksTestCase(SimpleTestCase):
         errors = FieldsetBookAdmin(Book, AdminSite()).check()
         expected = [
             checks.Error(
-                "The value of 'fieldsets[1][1][\"fields\"]' cannot include the ManyToManyField "
-                "'authors', because that field manually specifies a relationship model.",
+                "The value of 'fieldsets[1][1][\"fields\"]' cannot include the many-to-many field "
+                "'authors' because that field manually specifies a relationship model.",
                 obj=FieldsetBookAdmin,
                 id='admin.E013',
             )
diff --git a/tests/model_meta/tests.py b/tests/model_meta/tests.py
index cfae4736fa..d662c8257c 100644
--- a/tests/model_meta/tests.py
+++ b/tests/model_meta/tests.py
@@ -33,8 +33,7 @@ class OptionsBaseTests(SimpleTestCase):
             model = None
 
         field = relation if direct else relation.field
-        m2m = isinstance(field, related.ManyToManyField)
-        return relation, model, direct, m2m
+        return relation, model, direct, bool(field.many_to_many)  # many_to_many can be None
 
 
 class GetFieldsTests(OptionsBaseTests):
@@ -69,7 +68,7 @@ class DataTests(OptionsBaseTests):
 
     def test_local_fields(self):
         def is_data_field(f):
-            return isinstance(f, Field) and not isinstance(f, related.ManyToManyField)
+            return isinstance(f, Field) and not f.many_to_many
 
         for model, expected_result in TEST_RESULTS['local_fields'].items():
             fields = model._meta.local_fields
diff --git a/tests/modeladmin/tests.py b/tests/modeladmin/tests.py
index c7e4b2c29d..790d24f66d 100644
--- a/tests/modeladmin/tests.py
+++ b/tests/modeladmin/tests.py
@@ -633,7 +633,7 @@ class RawIdCheckTests(CheckTestCase):
 
         self.assertIsInvalid(
             ValidationTestModelAdmin, ValidationTestModel,
-            "The value of 'raw_id_fields[0]' must be a ForeignKey or ManyToManyField.",
+            "The value of 'raw_id_fields[0]' must be a foreign key or a many-to-many field.",
             'admin.E003')
 
     def test_valid_case(self):
@@ -826,7 +826,7 @@ class FilterVerticalCheckTests(CheckTestCase):
 
         self.assertIsInvalid(
             ValidationTestModelAdmin, ValidationTestModel,
-            "The value of 'filter_vertical[0]' must be a ManyToManyField.",
+            "The value of 'filter_vertical[0]' must be a many-to-many field.",
             'admin.E020')
 
     def test_valid_case(self):
@@ -863,7 +863,7 @@ class FilterHorizontalCheckTests(CheckTestCase):
 
         self.assertIsInvalid(
             ValidationTestModelAdmin, ValidationTestModel,
-            "The value of 'filter_horizontal[0]' must be a ManyToManyField.",
+            "The value of 'filter_horizontal[0]' must be a many-to-many field.",
             'admin.E020')
 
     def test_valid_case(self):
@@ -960,7 +960,7 @@ class PrepopulatedFieldsCheckTests(CheckTestCase):
         self.assertIsInvalid(
             ValidationTestModelAdmin, ValidationTestModel,
             ("The value of 'prepopulated_fields' refers to 'users', which must not be "
-             "a DateTimeField, ForeignKey or ManyToManyField."),
+             "a DateTimeField, a foreign key, or a many-to-many field."),
             'admin.E028')
 
     def test_valid_case(self):
@@ -998,7 +998,7 @@ class ListDisplayTests(CheckTestCase):
 
         self.assertIsInvalid(
             ValidationTestModelAdmin, ValidationTestModel,
-            "The value of 'list_display[0]' must not be a ManyToManyField.",
+            "The value of 'list_display[0]' must not be a many-to-many field.",
             'admin.E109')
 
     def test_valid_case(self):
diff --git a/tests/sites_framework/tests.py b/tests/sites_framework/tests.py
index 6d2717457a..de37bb5a00 100644
--- a/tests/sites_framework/tests.py
+++ b/tests/sites_framework/tests.py
@@ -62,7 +62,7 @@ class CurrentSiteManagerChecksTests(SimpleTestCase):
         expected = [
             checks.Error(
                 "CurrentSiteManager cannot use 'ConfusedArticle.site' as it is "
-                "not a ForeignKey or ManyToManyField.",
+                "not a foreign key or a many-to-many field.",
                 obj=ConfusedArticle.on_site,
                 id='sites.E002',
             )