Refs #36383 -- Added extra tests for serializing functools.partial in tests/migrations/test_writer.py.

This includes a test helper to better assert over the expected output.

Co-authored-by: Natalia <[email protected]>

Author: adamchainz

tests/migrations/test_writer.py

@@ -300,6 +300,18 @@ def assertSerializedFieldEqual(self, value):
         self.assertEqual(value.null, new_value.null)
         self.assertEqual(value.unique, new_value.unique)
 
+    def assertSerializedFunctoolsPartialEqual(
+        self, value, expected_string, expected_imports
+    ):
+        string, imports = MigrationWriter.serialize(value)
+        self.assertEqual(string, expected_string)
+        self.assertEqual(imports, expected_imports)
+        result = self.serialize_round_trip(value)
+        self.assertEqual(result.func, value.func)
+        self.assertEqual(result.args, value.args)
+        self.assertEqual(result.keywords, value.keywords)
+        return result
+
     def test_serialize_numbers(self):
         self.assertSerializedEqual(1)
         self.assertSerializedEqual(1.2)
@@ -895,19 +907,59 @@ def test_serialize_timedelta(self):
         self.assertSerializedEqual(datetime.timedelta(minutes=42))
 
     def test_serialize_functools_partial(self):
+        value = functools.partial(datetime.timedelta)
+        string, imports = MigrationWriter.serialize(value)
+        self.assertSerializedFunctoolsPartialEqual(
+            value,
+            "functools.partial(datetime.timedelta, *(), **{})",
+            {"import datetime", "import functools"},
+        )
+
+    def test_serialize_functools_partial_posarg(self):
+        value = functools.partial(datetime.timedelta, 1)
+        string, imports = MigrationWriter.serialize(value)
+        self.assertSerializedFunctoolsPartialEqual(
+            value,
+            "functools.partial(datetime.timedelta, *(1,), **{})",
+            {"import datetime", "import functools"},
+        )
+
+    def test_serialize_functools_partial_kwarg(self):
+        value = functools.partial(datetime.timedelta, seconds=2)
+        string, imports = MigrationWriter.serialize(value)
+        self.assertSerializedFunctoolsPartialEqual(
+            value,
+            "functools.partial(datetime.timedelta, *(), **{'seconds': 2})",
+            {"import datetime", "import functools"},
+        )
+
+    def test_serialize_functools_partial_mixed(self):
         value = functools.partial(datetime.timedelta, 1, seconds=2)
-        result = self.serialize_round_trip(value)
-        self.assertEqual(result.func, value.func)
-        self.assertEqual(result.args, value.args)
-        self.assertEqual(result.keywords, value.keywords)
+        string, imports = MigrationWriter.serialize(value)
+        self.assertSerializedFunctoolsPartialEqual(
+            value,
+            "functools.partial(datetime.timedelta, *(1,), **{'seconds': 2})",
+            {"import datetime", "import functools"},
+        )
+
+    def test_serialize_functools_partial_non_identifier_keyword(self):
+        value = functools.partial(datetime.timedelta, **{"kebab-case": 1})
+        string, imports = MigrationWriter.serialize(value)
+        self.assertSerializedFunctoolsPartialEqual(
+            value,
+            "functools.partial(datetime.timedelta, *(), **{'kebab-case': 1})",
+            {"import datetime", "import functools"},
+        )
 
     def test_serialize_functools_partialmethod(self):
         value = functools.partialmethod(datetime.timedelta, 1, seconds=2)
-        result = self.serialize_round_trip(value)
+        string, imports = MigrationWriter.serialize(value)
+        result = self.assertSerializedFunctoolsPartialEqual(
+            value,
+            "functools.partialmethod(datetime.timedelta, *(1,), **{'seconds': 2})",
+            {"import datetime", "import functools"},
+        )
         self.assertIsInstance(result, functools.partialmethod)
-        self.assertEqual(result.func, value.func)
-        self.assertEqual(result.args, value.args)
-        self.assertEqual(result.keywords, value.keywords)
 
     def test_serialize_type_none(self):
         self.assertSerializedEqual(NoneType)