document.put("string_field", "value1");
        document.put("string_array_field", new String[] { "value2", "value3" });
        document.put("list_field", java.util.Arrays.asList("value4", "value5"));
        document.put("int_field", 123);

        String[] stringValues = defaultContentsParser.getFieldValues(document, "string_field");
        assertEquals(1, stringValues.length);

    class ModelWithDatetimeField(BaseModel):
        dt_field: datetime

        @field_serializer("dt_field")
        def serialize_datetime(self, dt_field: datetime):
            return dt_field.replace(microsecond=0, tzinfo=timezone.utc).isoformat()

    app = FastAPI()
    model = ModelWithDatetimeField(dt_field=datetime(2019, 1, 1, 8))

    @app.get("/model", response_model=ModelWithDatetimeField)

        pass

    class MyDict(TypedDict):
        dt_field: safe_datetime

    instance = MyDict(dt_field=safe_datetime.now())

    encoded_instance = jsonable_encoder(
        instance, custom_encoder={safe_datetime: lambda o: o.strftime("%H:%M:%S")}
    )
    assert encoded_instance["dt_field"] == instance["dt_field"].strftime("%H:%M:%S")

    encoded_instance = jsonable_encoder(

                assertEquals("0", list.get(0).get(ID_FIELD));
                assertEquals("9", list.get(1).get(ID_FIELD));
                assertEquals("1", list.get(2).get(ID_FIELD));
                assertEquals("8", list.get(3).get(ID_FIELD));
                assertEquals("2", list.get(4).get(ID_FIELD));
                assertEquals("7", list.get(5).get(ID_FIELD));
                assertEquals("3", list.get(6).get(ID_FIELD));

 * Tests exception handling improvements including InterruptedException and ExecutionException.
 */
public class RankFusionProcessorErrorHandlingTest extends UnitFessTestCase {

    private static final String ID_FIELD = "_id";

    /**
     * Test handling of searcher that throws RuntimeException.
     */
    @Test
    public void test_searcherThrowsRuntimeException() throws Exception {

/**
 * Edge case tests for RankFusionProcessor.
 * Tests boundary conditions, empty states, and error scenarios.
 */
public class RankFusionProcessorEdgeCaseTest extends UnitFessTestCase {

    private static final String ID_FIELD = "_id";

    /**
     * Test behavior when no searchers are registered (empty list).
     */
    @Test
    public void test_emptySearcherList() throws Exception {

 * Tests the improvements made to thread safety using CopyOnWriteArrayList.
 */
public class RankFusionProcessorConcurrencyTest extends UnitFessTestCase {

    private static final String ID_FIELD = "_id";

    /**
     * Test concurrent registration of searchers from multiple threads.
     * Verifies that CopyOnWriteArrayList handles concurrent modifications safely.
     */
    @Test