Function schema

datafusion/core/tests/expr_api/simplification.rs:48–56

A schema like: a: Int32 (possibly with nulls) b: Int32 s: Utf8

()

/// b: Int32
/// s: Utf8
fn schema() -> DFSchemaRef {
    Schema::new(vec![
        Field::new("a", DataType::Int32, true),
        Field::new("b", DataType::Int32, false),
        Field::new("s", DataType::Utf8, false),
    ])
    .to_dfschema_ref()
    .unwrap()
}

fn test_table_scan() -> LogicalPlan {
    let schema = Schema::new(vec![