{* ../../docs_src/response_directly/tutorial002_py310.py hl[1,18] *}

## Cómo funciona un Response Model { #how-a-response-model-works }

Cuando declaras un [Response Model - Return Type](../tutorial/response-model.md) en una *path operation*, **FastAPI** lo usará para serializar los datos a JSON, usando Pydantic.

{* ../../docs_src/response_model/tutorial001_01_py310.py hl[16,21] *}

Також зверніть увагу, що **FastAPI** достатньо розумний, щоб визначити, що параметр шляху `item_id` є параметром шляху, а `q` — ні, отже, це параметр query.

///

## Перетворення типу параметра query { #query-parameter-type-conversion }

Ви також можете оголошувати параметри типу `bool`, і вони будуть автоматично конвертовані:

{* ../../docs_src/query_params/tutorial003_py310.py hl[7] *}

У цьому випадку, якщо ви перейдете за:

```

			if res.StatusCode != expectStatus {
				t.Errorf("Expected status %d, got %d", expectStatus, res.StatusCode)
			}

			if contentType != "" {
				if ct := res.Header.Get("Content-Type"); ct != contentType {
					t.Errorf("Expected Content-Type %q, got %q", contentType, ct)
				}
			}

			if res.StatusCode < 400 {
				if string(respBody) != lambdaBody {
					t.Errorf("Expected body %q, got %q", lambdaBody, string(respBody))

        enablePullRequestFeature()
    }

    requirements {
        requiresOs(os)
        requiresArch(os, arch)
    }

    failureConditions {
        if (this@applyDefaultSettings.type != BuildTypeSettings.Type.COMPOSITE) {
            executionTimeoutMin = timeout
        }
        testFailure = true
        supportTestRetry = true
        add {
            failOnText {

  <Description>Full Text Search for Your Documents.</Description>
  <Tags>Full Text Search</Tags>
  <Contact>******@****.***</Contact>
  <SearchForm>http://localhost:8080/fess/</SearchForm>
  <Url type="text/html" template="http://localhost:8080/fess/search?q={searchTerms}"/>
  <InputEncoding>UTF-8</InputEncoding>
  <OutputEncoding>UTF-8</OutputEncoding>

rm:none}[role=button]{cursor:pointer}select{word-wrap:normal}[type=button],[type=reset],[type=submit],button{-webkit-appearance:button}[type=button]:not(:disabled),[type=reset]:not(:disabled),[type=submit]:not(:disabled),button:not(:disabled){cursor:pointer}[type=button]::-moz-focus-inner,[type=reset]::-moz-focus-inner,[type=submit]::-moz-focus-inner,button::-moz-focus-inner{padding:0;border-style:none}input[type=checkbox],input[type=radio]{box-sizing:border-box;padding:0}textarea{overflow:auto;...

/**
 * Base class for map testers.
 *
 * <p>TODO: see how much of this is actually needed once Map testers are written. (It was cloned
 * from AbstractCollectionTester.)
 *
 * @param <K> the key type of the map to be tested.
 * @param <V> the value type of the map to be tested.
 * @author George van den Driessche
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")

    builder.add(Range.<Integer>all());

    // Add one-ended ranges
    for (int i = MIN_BOUND; i <= MAX_BOUND; i++) {
      for (BoundType type : BoundType.values()) {
        builder.add(Range.upTo(i, type));
        builder.add(Range.downTo(i, type));
      }
    }

    // Add two-ended ranges
    for (int i = MIN_BOUND; i <= MAX_BOUND; i++) {
      for (int j = i + 1; j <= MAX_BOUND; j++) {

		// ListObjectsV2M
		router.Methods(http.MethodGet).
			HandlerFunc(s3APIMiddleware(api.ListObjectsV2MHandler)).
			Queries("list-type", "2", "metadata", "true")
		// ListObjectsV2
		router.Methods(http.MethodGet).
			HandlerFunc(s3APIMiddleware(api.ListObjectsV2Handler)).
			Queries("list-type", "2")
		// ListObjectVersions
		router.Methods(http.MethodGet).
			HandlerFunc(s3APIMiddleware(api.ListObjectVersionsMHandler)).

from fastapi import FastAPI
from fastapi.params import Param
from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/items/")
def read_items(q: str | None = Param(default=None)):  # type: ignore
    return {"q": q}


client = TestClient(app)


def test_default_param_query_none():
    response = client.get("/items/")
    assert response.status_code == 200, response.text
    assert response.json() == {"q": None}