///

FastAPI ahora:

* **Validará** los datos asegurándose de que la longitud máxima sea de 50 caracteres
* Mostrará un **error claro** para el cliente cuando los datos no sean válidos
* **Documentará** el parámetro en el OpenAPI esquema *path operation* (así aparecerá en la **UI de documentación automática**)

        }

        @Override
        public SSPContext createContext(CIFSContext tc, String targetDomain, String host, byte[] initialToken, boolean doSigning)
                throws SmbException {
            // Validate required argument and interact with the provided CIFSContext
            if (tc == null) {
                throw new NullPointerException("tc");
            }

        assertEquals("childuser", testConfig.getDefaultUsername()); // Overridden
        assertEquals("parentdomain", testConfig.getDefaultDomain()); // Inherited
    }

    @Test
    @DisplayName("Should validate configuration consistency")
    void testConfigurationValidation() throws CIFSException {
        // Given
        Properties props = new Properties();
        props.setProperty("jcifs.smb.client.minVersion", "SMB311");

        // Act & Assert: attempting to call any method on null should throw NPE
        Assertions.assertThrows(NullPointerException.class, () -> {
            // Intentionally dereference null to validate exception behavior
            // This checks that callers must handle null references defensively
            info.getSize();
        });
    }

```

</div>

Then go to the `/docs` UI, you will see that **FastAPI** is using these **models** to **document** the API, and it will use them to **serialize** and **validate** the data too.

<div class="screenshot">
<img src="/img/tutorial/sql-databases/image01.png">
</div>

## Update the App with Multiple Models { #update-the-app-with-multiple-models }

        Address address = nameServiceClient.getByName("localhost", false);

        // Then
        assertNotNull(address, "Should return address for localhost");
    }

    @Test
    @DisplayName("Should validate context configuration access")
    void testContextAccess() {
        // When
        NameServiceClientImpl client = new NameServiceClientImpl(mockContext);

        // Then

	setCrossDomainPolicyMiddleware,
	// Limits all body and header sizes to a maximum fixed limit
	setRequestLimitMiddleware,
	// Validate all the incoming requests.
	setRequestValidityMiddleware,
	// Add upload forwarding middleware for site replication
	setUploadForwardingMiddleware,
	// Add bucket forwarding middleware
	setBucketForwardingMiddleware,
	// Add new middlewares here.
}

# ----------------------------------------------------------
# Hibernate Validator
# -------------------
constraints.CreditCardNumber.message = {item} est un numéro de carte de crédit non valide.
constraints.EAN.message = {item} est un code-barres {type} non valide.
constraints.Email.message = {item} n'est pas une adresse e-mail valide.
constraints.Length.message = La longueur de {item} doit être comprise entre {min} et {max}.

errors.header = <ul class="has-error">
errors.footer = </ul>
errors.prefix = <li><i class="fa fa-exclamation-circle"></i>
errors.suffix = </li>
# ----------------------------------------------------------
# Javax Validator
# ---------------
constraints.AssertFalse.message = {item} 必须为 false。
constraints.AssertTrue.message = {item} 必须为 true。
constraints.DecimalMax.message = {item} 必须小于 {value}。

  bufferA.writeUtf8(normalized)

  // 3. For each label, convert/validate Punycode.
  val decoded = Punycode.decode(bufferA.readUtf8()) ?: return null

  // 4.1 Validate.

  // Must be NFC.
  if (decoded != normalizeNfc(decoded)) return null

  // TODO: Must not begin with a combining mark.
  // TODO: Each character must be 'valid' or 'deviation'. Not mapped.
  // TODO: CheckJoiners from IDNA 2008