if route.response_fields:
                responses_from_routes.extend(route.response_fields.values())
            if route.callbacks:
                callback_flat_models.extend(get_fields_from_routes(route.callbacks))
            params = get_flat_params(route.dependant)
            request_fields_from_routes.extend(params)

    flat_models = callback_flat_models + list(

        flat_dependant.path_params.extend(flat_sub.path_params)
        flat_dependant.query_params.extend(flat_sub.query_params)
        flat_dependant.header_params.extend(flat_sub.header_params)
        flat_dependant.cookie_params.extend(flat_sub.cookie_params)
        flat_dependant.body_params.extend(flat_sub.body_params)
        flat_dependant.dependencies.extend(flat_sub.dependencies)

    return flat_dependant

    en_links.sort(key=lambda x: x.preview_link)
    links.extend(en_links)

    langs = list(lang_links.keys())
    langs.sort()
    for lang in langs:
        if lang == "en":
            continue
        current_lang_links = lang_links[lang]
        current_lang_links.sort(key=lambda x: x.preview_link)
        links.extend(current_lang_links)

    header = "## 📝 Docs preview"
    message = header

/// tip

This is a low level extension point.

If you only need to declare additional responses, a more convenient way to do it is with [Additional Responses in OpenAPI](additional-responses.md){.internal-link target=_blank}.

///

You can extend the OpenAPI schema for a *path operation* using the parameter `openapi_extra`.

            // The actual logic is tested in AbstractUpgradeGoalTest
            // Here we just verify that Apply is properly configured as a subclass
            assertInstanceOf(AbstractUpgradeGoal.class, applyGoal, "Apply should extend AbstractUpgradeGoal");
            assertTrue(applyGoal.shouldSaveModifications(), "Apply should save modifications unlike Check goal");
        }
    }

 * }</pre>
 *
 * <h2>Extension Points</h2>
 *
 * <p>To add new upgrade strategies:</p>
 * <ol>
 *   <li>Implement {@link org.apache.maven.cling.invoker.mvnup.goals.UpgradeStrategy}</li>
 *   <li>Optionally extend {@link org.apache.maven.cling.invoker.mvnup.goals.AbstractUpgradeStrategy}</li>
 *   <li>Annotate with {@code @Named} and {@code @Singleton}</li>
 *   <li>Use {@code @Priority} to control execution order</li>
 * </ol>
 *

 * constructed instance. To create session out of builder, use {@link SessionBuilder#build()}. For proper closing
 * of sessions, use {@link CloseableSession#close()} method on built instance(s).
 * <p>
 * Extend this class and override methods to customize, if needed.
 *
 * @since 4.0.0
 * @deprecated since 4.0.0, use {@code maven-api-impl} jar instead
 */
@Deprecated(since = "4.0.0")

{* ../../docs_src/app_testing/app_a_py39/test_main.py hl[3] *}


...and have the code for the tests just like before.

## Testing: extended example { #testing-extended-example }

Now let's extend this example and add more details to see how to test different parts.

### Extended **FastAPI** app file { #extended-fastapi-app-file }

Let's continue with the same file structure as before:

```
.

                    current_tags.extend(tags)
                if route.tags:
                    current_tags.extend(route.tags)
                current_dependencies: list[params.Depends] = []
                if dependencies:
                    current_dependencies.extend(dependencies)
                if route.dependencies:
                    current_dependencies.extend(route.dependencies)

    agent = Agent("openai:gpt-5.2")

    prompt_segments = [
        general_prompt,
        lang_prompt_content,
    ]
    if old_translation:
        prompt_segments.extend(
            [
                "There is an existing previous translation for the original English content, that may be outdated.",
                "Update the translation only where necessary:",