assertEquals(1, (int) iter.peek());
    assertEquals(1, (int) iter.next());

    /*
     * We test peek() after various calls to make sure that one bad call doesn't interfere with its
     * ability to throw the correct exception in the future.
     */
    assertThrows(NoSuchElementException.class, iter::peek);
    assertThrows(NoSuchElementException.class, iter::peek);
    assertThrows(NoSuchElementException.class, iter::next);

    assertEquals(1, (int) iter.peek());
    assertEquals(1, (int) iter.next());

    /*
     * We test peek() after various calls to make sure that one bad call doesn't interfere with its
     * ability to throw the correct exception in the future.
     */
    assertThrows(NoSuchElementException.class, iter::peek);
    assertThrows(NoSuchElementException.class, iter::peek);
    assertThrows(NoSuchElementException.class, iter::next);

    private static final int TEST_FID = 0x1234;

    @BeforeEach
    void setUp() {
        MockitoAnnotations.openMocks(this);
    }

    @Test
    @DisplayName("Constructor should initialize with correct values")
    void testConstructor() {
        // Act
        transPeekNamedPipe = new TransPeekNamedPipe(mockConfig, TEST_PIPE_NAME, TEST_FID);

        // Assert
        assertNotNull(transPeekNamedPipe);

This gives you a lot of **flexibility**. You can return any data type, override any data declaration or validation, etc.

It also gives you a lot of **responsibility**. You have to make sure that the data you return is correct, in the correct format, that it can be serialized, etc.

## Using the `jsonable_encoder` in a `Response` { #using-the-jsonable-encoder-in-a-response }

Você verá a documentação automática da API para a sub-aplicação, incluindo apenas suas próprias _operações de rota_, todas sob o prefixo de sub-path correto `/subapi`:

<img src="/img/tutorial/sub-applications/image02.png">

        assertNotNull(authenticator);
    }

    @Test
    public void test_defaultSettings_emailAddressCorrect() throws Exception {
        // Test that the email typo fix is correct: support@@example.com -> ******@****.***
        Map<String, Object> defaultSettings = createDefaultSettings();

        // Verify email addresses are correctly formatted (no double @)

    if (dividend >= 0) {
      return dividend / divisor;
    }

    /*
     * Otherwise, approximate the quotient, check, and correct if necessary. Our approximation is
     * guaranteed to be either exact or one less than the correct value. This follows from fact that
     * floor(floor(x)/i) == floor(x/i) for any real x and integer i != 0. The proof is not quite
     * trivial.
     */

    assertEquals("correct", f.apply(new Object()));
    assertEquals("correct", f.apply(null));

    Function<@Nullable Object, @Nullable String> g = Functions.constant(null);
    assertThat(g.apply(2)).isNull();
    assertThat(g.apply(null)).isNull();

    new EqualsTester()
        .addEqualityGroup(f, Functions.constant("correct"))

</div>

E abra a documentação em [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs).

Você verá a documentação automática da API, incluindo os paths de todos os submódulos, usando os paths (e prefixos) corretos e as tags corretas:

<img src="/img/tutorial/bigger-applications/image01.png">

## Inclua o mesmo router várias vezes com `prefix` diferentes { #include-the-same-router-multiple-times-with-different-prefix }

## Recap { #recap }

You can add multiple body parameters to your *path operation function*, even though a request can only have a single body.

But **FastAPI** will handle it, give you the correct data in your function, and validate and document the correct schema in the *path operation*.

You can also declare singular values to be received as part of the body.