Function get_random_function

datafusion/core/tests/fuzz_cases/window_fuzz.rs:329–459

(
    schema: &SchemaRef,
    rng: &mut StdRng,
    is_linear: bool,
)

}

fn get_random_function(
    schema: &SchemaRef,
    rng: &mut StdRng,
    is_linear: bool,
) -> (WindowFunctionDefinition, Vec<Arc<dyn PhysicalExpr>>, String) {
    let arg = if is_linear {
        // In linear test for the test version with WindowAggExec we use insert SortExecs to the plan to be able to generate
        // same result with BoundedWindowAggExec which doesn't use any SortExec. To make result
        // non-dependent on table order. We should use column a in the window function
        // (Given that we do not use ROWS for the window frame. ROWS also introduces dependency to the table order.).
        col("a", schema).unwrap()
    } else {
        col("x", schema).unwrap()
    };
    let mut window_fn_map = HashMap::new();
    // HashMap values consists of tuple first element is WindowFunction, second is additional argument
    // window function requires if any. For most of the window functions additional argument is empty
    window_fn_map.insert(
        "sum",
        (
            WindowFunctionDefinition::AggregateUDF(sum_udaf()),
            vec![arg.clone()],
        ),
    );
    window_fn_map.insert(
        "count",
        (
            WindowFunctionDefinition::AggregateUDF(count_udaf()),
            vec![arg.clone()],
        ),
    );
    window_fn_map.insert(
        "min",
        (
            WindowFunctionDefinition::AggregateUDF(min_udaf()),
            vec![arg.clone()],
        ),
    );
    window_fn_map.insert(
        "max",
        (
            WindowFunctionDefinition::AggregateUDF(max_udaf()),
            vec![arg.clone()],
        ),
    );
    if !is_linear {
        // row_number, rank, lead, lag doesn't use its window frame to calculate result. Their results are calculated
        // according to table scan order. This adds the dependency to table order. Hence do not use these functions in
        // Partition by linear test.
        window_fn_map.insert(
            "row_number",
            (
                WindowFunctionDefinition::WindowUDF(row_number_udwf()),
                vec![],
            ),
        );
        window_fn_map.insert(
            "rank",