{* ../../docs_src/stream_json_lines/tutorial001_py310.py ln[1:24] hl[9:11,22] *}

If you declare the return type, FastAPI will use it to **validate** the data, **document** it in OpenAPI, **filter** it, and **serialize** it using Pydantic.

/// tip

        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
     */
    protected Boolean isValidWebConfigId(final String webconfigId) {

        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
     */
    protected Boolean isValidWebConfigId(final String webconfigId) {

import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;

/**
 * Tests for SmbFilenameFilter interface behaviors via simple implementations.
 * Each test creates a concrete filter to validate expected contract semantics
 * including normal operation, null handling, edge cases, and exception flow.
 */
@ExtendWith(MockitoExtension.class)
class SmbFilenameFilterTest {

    @Mock
    SmbFile mockDir;

        when(otherContext.getConfig()).thenReturn(otherConfig);
        assertFalse(response.canReuse(otherContext, false));
    }

    @Test
    @DisplayName("Should validate response correctly")
    void testIsValid() throws Exception {
        // Setup valid response
        setResponseAsReceived(response);
        setPrivateField(response, "dialectRevision", 0x0311);

	// End is the offset of the last byte that should be returned when Start
	// is set, otherwise it is the offset from EOF to start reading.
	End *uint64 `xml:"End"`
}

// Validate if the scan range is valid.
func (s *ScanRange) Validate() error {
	if s == nil {
		return nil
	}
	if s.Start == nil && s.End == nil {
		// This parameter is optional, but when specified, it must not be empty.

    }

    @Test
    @DisplayName("Arrays: non-null, same length, and exact contents")
    void arrays_are_well_formed_and_match() {
        // Validate arrays existence and alignment (edge and structure checks)
        assertNotNull(WinError.WINERR_CODES, "WINERR_CODES should not be null");
        assertNotNull(WinError.WINERR_MESSAGES, "WINERR_MESSAGES should not be null");

        byte[] buffer = new byte[20];
        int len = cmd.writeParameterWordsWireFormat(buffer, 0);
        assertEquals(-12, len, "writeParameterWordsWireFormat should write 12 Bytes");
        // Validate parameter bytes using reflection since fields are private
        assertEquals(getField(cmd, "fid"), SMBUtil.readInt2(buffer, 0));
        assertEquals(getField(cmd, "typeOfLock"), buffer[2]);

        // This test validates integration patterns without requiring real cluster

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

        // Test witness client initialization patterns
        assertDoesNotThrow(() -> {
            // Validate that witness client configuration is properly set up

## Troubleshooting

### Common Migration Issues

#### Issue: Import fails with "Invalid format"

**Solution**:
- Ensure NDJSON files have one valid JSON object per line
- Check for UTF-8 encoding
- Validate JSON syntax with `jq`:
  ```bash
  cat documents.ndjson | jq empty
  ```

#### Issue: GSA XML import creates no configurations

**Solution**:
- Verify XML structure matches GSA export format