* @return ActionResponse containing the cached document content or error redirect
     */
    @Execute
    public ActionResponse index(final CacheForm form) {
        validate(form, messages -> {}, () -> asHtml(virtualHost(path_Error_ErrorJsp)));
        if (isLoginRequired()) {
            return redirectToLogin();
        }

        Map<String, Object> doc = null;
        try {

		case isSysErrTooManyFiles(err):
			return nil, dmTime, errTooManyOpenFiles
		case isSysErrInvalidArg(err):
			st, _ := Lstat(filePath)
			if st != nil && st.IsDir() {
				// Linux returns InvalidArg for directory O_DIRECT
				// we need to keep this fallback code to return correct
				// errors upwards.
				return nil, dmTime, errFileNotFound
			}
			return nil, dmTime, errUnsupportedDisk
		}

        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

import org.junit.jupiter.api.Timeout;
import org.mockito.Mockito;

import jcifs.CIFSContext;
import jcifs.Configuration;
import jcifs.Credentials;

/**
 * Simple memory management tests to validate basic resource cleanup functionality
 */
public class SimpleMemoryManagementTest {

    private CIFSContext mockContext;
    private SmbTransportImpl mockTransport;
    private Configuration mockConfig;

import jcifs.SmbTree;
import jcifs.internal.CommonServerMessageBlockResponse;
import jcifs.internal.Request;

/**
 * Tests for SmbTreeInternal interface behavior via mocks.
 * Since this is an interface, we validate its public API contract
 * through interaction testing and generic type usage.
 */
@ExtendWith(MockitoExtension.class)
class SmbTreeInternalTest {

    @Mock
    private SmbTreeInternal tree;

    @Mock

	// request and proceed further. This is a work-around to address
	// an important problem for ListBuckets() getting signed with
	// different regions.
	if region == "" {
		region = sRegion
	}
	// Should validate region, only if region is set.
	if !isValidRegion(sRegion, region) {
		return ch, ErrAuthorizationHeaderMalformed
	}
	if credElements[2] != string(stype) {
		if stype == serviceSTS {

```

</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 }

	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}
	region := globalSite.Region()
	config.SetRegion(region)
	if err = config.Validate(region, globalEventNotifier.targetList); err != nil {
		arnErr, ok := err.(*event.ErrARNNotFound)
		if ok {
			for i, queue := range config.QueueList {
				// Remove ARN not found queues, because we previously allowed

	// Adds 'crossdomain.xml' policy middleware to serve legacy flash clients.
	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,

// ----------
// Enable server profiling
func (a adminAPIHandlers) StartProfilingHandler(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	// Validate request signature.
	_, adminAPIErr := checkAdminRequestAuth(ctx, r, policy.ProfilingAdminAction, "")
	if adminAPIErr != ErrNone {
		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(adminAPIErr), r.URL)
		return