// Extreme TDD test to expose and fix arrow Fields conversion bug
// Following Toyota Way: Write test FIRST, then fix implementation

#[test]
fn test_fields_conversion_requirement() {
    // TDD: This test exposes the Fields conversion issue
    // Bug location: src/backend/arrow_integration.rs:36
    // Known bug: ArrowSchema::new expects Fields but we provide Vec<ArrowField>

    // The error shows these valid conversions:
    // Fields implements From<&[Arc<arrow_schema::Field>]>
    // Fields implements From<Vec<Arc<arrow_schema::Field>>>
    // Fields implements From<Vec<arrow_schema::Field>>

    let expected_conversions = [
        "From<&[Arc<arrow_schema::Field>]>",
        "From<Vec<Arc<arrow_schema::Field>>>",
        "From<Vec<arrow_schema::Field>>",
    ];

    // Our current type: Vec<ArrowField> (from polars)
    // Target type: Fields (from arrow_schema)

    assert_eq!(expected_conversions.len(), 3);

    // Strategy: Convert Vec<ArrowField> to compatible type
    let needs_conversion = true;
    assert!(needs_conversion);
}

#[test]
fn test_arc_wrapping_strategy() {
    // TDD: This test documents the Arc wrapping approach

    // Pattern: Vec<T> -> Vec<Arc<T>>
    let items = vec!["field1", "field2"];
    let arc_items: Vec<std::sync::Arc<&str>> = items.into_iter().map(std::sync::Arc::new).collect();

    assert_eq!(arc_items.len(), 2);

    // This pattern should work for our fields:
    // Vec<ArrowField> -> Vec<Arc<ArrowField>> -> Fields
    let conversion_strategy = "map(Arc::new)";
    assert_eq!(conversion_strategy, "map(Arc::new)");
}
