Add test, fix iteration error

api/api/openapi.py

@@ -36,7 +36,7 @@ def get_response_schemas(
     ) -> dict[str, Response]:
         result = {}
 
-        for status_code in response_serializers:
+        for status_code in list(response_serializers):
             if isinstance(response_serializers[status_code], type) and issubclass(
                 model_cls := response_serializers[status_code], BaseModel
             ):

api/tests/unit/api/test_unit_openapi.py

@@ -0,0 +1,71 @@
+import pydantic
+from drf_yasg.openapi import (
+    SCHEMA_DEFINITIONS,
+    ReferenceResolver,
+    Response,
+    Schema,
+)
+from pytest_mock import MockerFixture
+
+from api.openapi import PydanticResponseCapableSwaggerAutoSchema
+
+
+def test_pydantic_response_capable_auto_schema__renders_expected(
+    mocker: MockerFixture,
+) -> None:
+    # Given
+    class Nested(pydantic.BaseModel):
+        usual_str: str
+        optional_int: int | None = None
+
+    class ResponseModel(pydantic.BaseModel):
+        nested_once: Nested
+        nested_list: list[Nested]
+
+    auto_schema = PydanticResponseCapableSwaggerAutoSchema(
+        view=mocker.MagicMock(),
+        path=mocker.MagicMock(),
+        method=mocker.MagicMock(),
+        components=ReferenceResolver("definitions", force_init=True),
+        request=mocker.MagicMock(),
+        overrides=mocker.MagicMock(),
+    )
+
+    # When
+    response_schemas = auto_schema.get_response_schemas({200: ResponseModel})
+
+    # Then
+    assert response_schemas == {
+        "200": Response(
+            description="ResponseModel",
+            schema=Schema(
+                title="ResponseModel",
+                required=["nested_once", "nested_list"],
+                type="object",
+                properties={
+                    "nested_list": {
+                        "items": {"$ref": "#/definitions/Nested"},
+                        "title": "Nested List",
+                        "type": "array",
+                    },
+                    "nested_once": {"$ref": "#/definitions/Nested"},
+                },
+            ),
+        ),
+    }
+    nested_schema = auto_schema.components.with_scope(SCHEMA_DEFINITIONS).get("Nested")
+    assert nested_schema == Schema(
+        title="Nested",
+        required=["usual_str"],
+        type="object",
+        properties={
+            "optional_int": {
+                "default": None,
+                "title": "Optional Int",
+                "type": "integer",
+                "x-nullable": True,
+            },
+            "usual_str": {"title": "Usual Str", "type": "string"},
+        },
+        x_nullable=True,
+    )