qubit-function 0.18.0

Functional programming traits and Box/Rc/Arc adapters for Rust, inspired by Java functional interfaces
// =============================================================================
//    Copyright (c) 2025 - 2026 Haixing Hu.
//
//    SPDX-License-Identifier: Apache-2.0
//
//    Licensed under the Apache License, Version 2.0.
// =============================================================================
use qubit_function::{
    ArcBiTransformer,
    BiTransformer,
    BoxBiTransformer,
    RcBiTransformer,
};
use std::thread;

// ============================================================================
// BoxBiTransformer Tests - Immutable, single ownership
// ============================================================================

#[cfg(test)]
mod trait_usage_tests {
    use super::{
        BiTransformer,
        BoxBiTransformer,
    };

    #[test]
    fn test_bi_transformer_trait() {
        fn apply_bi_transformer<F: BiTransformer<i32, i32, i32>>(
            f: &F,
            x: i32,
            y: i32,
        ) -> i32 {
            f.apply(x, y)
        }

        let add = BoxBiTransformer::new(|x: i32, y: i32| x + y);
        assert_eq!(apply_bi_transformer(&add, 20, 22), 42);
    }

    #[test]
    fn test_closure_as_bi_transformer() {
        fn apply_bi_transformer<F: BiTransformer<i32, i32, i32>>(
            f: &F,
            x: i32,
            y: i32,
        ) -> i32 {
            f.apply(x, y)
        }

        let add = |x: i32, y: i32| x + y;
        assert_eq!(apply_bi_transformer(&add, 20, 22), 42);
    }

    #[test]
    fn test_with_different_types() {
        fn apply_bi_transformer<T, U, R, F: BiTransformer<T, U, R>>(
            f: &F,
            x: T,
            y: U,
        ) -> R {
            f.apply(x, y)
        }

        let format = BoxBiTransformer::new(|name: String, age: i32| {
            format!("{} is {}", name, age)
        });
        assert_eq!(
            apply_bi_transformer(&format, "Alice".to_string(), 30),
            "Alice is 30"
        );
    }
}

// ============================================================================
// Edge Cases Tests
// ============================================================================