if err := e.EncodeElement(f.Prefix, xml.StartElement{Name: xml.Name{Local: "Prefix"}}); err != nil {
			return err
		}
	}

	return e.EncodeToken(xml.EndElement{Name: start.Name})
}

// Validate - validates the filter element
func (f Filter) Validate() error {
	// A Filter must have exactly one of Prefix, Tag, or And specified.
	if !f.And.isEmpty() {
		if f.Prefix != "" {
			return errInvalidFilter
		}

* **Розширюваність**:
    * Pydantic дозволяє визначати користувацькі типи даних або ви можете розширити валідацію методами в моделі, позначеними декоратором validator.

## Official Guide { #official-guide }

Pydantic has an official [Migration Guide](https://docs.pydantic.dev/latest/migration/) from v1 to v2.

It also includes what has changed, how validations are now more correct and strict, possible caveats, etc.

You can read it to understand better what has changed.

## Tests { #tests }

Wenn Sie FastAPI mit `pip install "fastapi[standard]"` installieren, kommt es mit der `standard`-Gruppe optionaler Abhängigkeiten:

Verwendet von Pydantic:

* [`email-validator`](https://github.com/JoshData/python-email-validator) – für E-Mail-Validierung.

Verwendet von Starlette:

* [`httpx`](https://www.python-httpx.org) – erforderlich, wenn Sie den `TestClient` verwenden möchten.

@ExtendWith(MockitoExtension.class)
class CredentialsInternalTest {

    @Mock
    CIFSContext mockContext;

    /**
     * Simple in-test implementation of CredentialsInternal to exercise the API surface.
     * It validates inputs, records calls, and delegates some behavior to collaborators
     * so we can verify interactions.
     */
    static class TestCredentials implements CredentialsInternal {
        private final String domain;

        final EditBody body = new EditBody();
        copyBeanToBean(entity, body, copyOp -> {
            copyOp.excludeNull();
        });
        return body;
    }

    /**
     * Validates if the given web configuration ID exists.
     *
     * @param webconfigId the web configuration ID to validate
     * @return true if the web configuration exists, false otherwise
     */

        final EditBody body = new EditBody();
        copyBeanToBean(entity, body, copyOp -> {
            copyOp.excludeNull();
        });
        return body;
    }

    /**
     * Validates if the given web configuration ID exists.
     *
     * @param webconfigId the web configuration ID to validate
     * @return true if the web configuration exists, false otherwise
     */

func ParseBucketSSEConfig(r io.Reader) (*BucketSSEConfig, error) {
	var config BucketSSEConfig
	err := xml.NewDecoder(r).Decode(&config)
	if err != nil {
		return nil, err
	}

	// Validates server-side encryption config rules
	// Only one rule is allowed on AWS S3
	if len(config.Rules) != 1 {
		return nil, errors.New("only one server-side encryption rule is allowed at a time")
	}

FastAPI 依赖 Pydantic 和 Starlette。

### `standard` 依赖 { #standard-dependencies }

当你通过 `pip install "fastapi[standard]"` 安装 FastAPI 时，会包含 `standard` 组的一些可选依赖：

Pydantic 使用：

* [`email-validator`](https://github.com/JoshData/python-email-validator) - 用于 email 校验。

Starlette 使用：

* [`httpx`](https://www.python-httpx.org) - 使用 `TestClient` 时需要。
* [`jinja2`](https://jinja.palletsprojects.com) - 使用默认模板配置时需要。

     */
    @Test
    void testWitnessEnvironmentConfiguration() throws Exception {
        // Test simulating real witness environment scenarios
        // This test validates integration patterns without requiring real cluster

        // Simulate witness service discovery
        InetAddress mockWitnessAddress = InetAddress.getByName("127.0.0.1");