Refs #33916 -- Added tests for serialization of enum.Flag in migrations.

tests/migrations/test_writer.py

@@ -80,6 +80,11 @@ class IntEnum(enum.IntEnum):
     B = 2
 
 
+class IntFlagEnum(enum.IntFlag):
+    A = 1
+    B = 2
+
+
 class OperationWriterTests(SimpleTestCase):
     def test_empty_signature(self):
         operation = custom_migration_operations.operations.TestOperation()
@@ -382,6 +387,33 @@ class WriterTests(SimpleTestCase):
             "default=migrations.test_writer.IntEnum['A'])",
         )
 
+    def test_serialize_enum_flags(self):
+        self.assertSerializedResultEqual(
+            IntFlagEnum.A,
+            (
+                "migrations.test_writer.IntFlagEnum['A']",
+                {"import migrations.test_writer"},
+            ),
+        )
+        self.assertSerializedResultEqual(
+            IntFlagEnum.B,
+            (
+                "migrations.test_writer.IntFlagEnum['B']",
+                {"import migrations.test_writer"},
+            ),
+        )
+        field = models.IntegerField(
+            default=IntFlagEnum.A, choices=[(m.value, m) for m in IntFlagEnum]
+        )
+        string = MigrationWriter.serialize(field)[0]
+        self.assertEqual(
+            string,
+            "models.IntegerField(choices=["
+            "(1, migrations.test_writer.IntFlagEnum['A']), "
+            "(2, migrations.test_writer.IntFlagEnum['B'])], "
+            "default=migrations.test_writer.IntFlagEnum['A'])",
+        )
+
     def test_serialize_choices(self):
         class TextChoices(models.TextChoices):
             A = "A", "A value"