announcement/tests/trait_impl_tests.rs

//! Tests for trait implementations (Display, Error, Debug, etc.)
//!
//! These tests ensure that all trait implementations are properly covered
//! by the test suite, particularly for error types.

use announcement::{AnnounceError, Announcement, ListenError};
use std::error::Error;

// =============================================================================
// AnnounceError Trait Implementation Tests
// =============================================================================

/// Test: Trait test: announce error display
///
/// Verifies: Verifies announce error display
/// Category: trait
#[test]
fn test_announce_error_display() {
    let err = AnnounceError::AlreadyAnnounced(42);
    let display_str = format!("{}", err);
    assert_eq!(display_str, "a value has already been announced");
}

/// Test: Trait test: announce error display string type
///
/// Verifies: Verifies announce error display string type
/// Category: trait
#[test]
fn test_announce_error_display_string_type() {
    let err = AnnounceError::AlreadyAnnounced("test".to_string());
    let display_str = format!("{}", err);
    assert_eq!(display_str, "a value has already been announced");
}

/// Test: Trait test: announce error to string
///
/// Verifies: Verifies announce error to string
/// Category: trait
#[test]
fn test_announce_error_to_string() {
    let err = AnnounceError::AlreadyAnnounced(99);
    assert_eq!(err.to_string(), "a value has already been announced");
}

/// Test: Trait test: announce error std error trait
///
/// Verifies: Verifies announce error std error trait
/// Category: trait
#[test]
fn test_announce_error_std_error_trait() {
    let err = AnnounceError::AlreadyAnnounced(42);
    // Verify it implements std::error::Error by using it as a trait object
    let _err_ref: &dyn Error = &err;
    // Verify source() returns None (default implementation)
    assert!(err.source().is_none());
}

/// Test: Trait test: announce error debug
///
/// Verifies: Verifies announce error debug
/// Category: trait
#[test]
fn test_announce_error_debug() {
    let err = AnnounceError::AlreadyAnnounced(42);
    let debug_str = format!("{:?}", err);
    assert!(debug_str.contains("AlreadyAnnounced"));
    assert!(debug_str.contains("42"));
}

// =============================================================================
// ListenError Trait Implementation Tests
// =============================================================================

/// Test: Trait test: listen error timeout display
///
/// Verifies: Verifies listen error timeout display
/// Category: trait
#[test]
fn test_listen_error_timeout_display() {
    let err = ListenError::Timeout;
    let display_str = format!("{}", err);
    assert_eq!(
        display_str,
        "timeout elapsed while waiting for announcement"
    );
}

/// Test: Trait test: listen error closed display
///
/// Verifies: Verifies listen error closed display
/// Category: trait
#[test]
fn test_listen_error_closed_display() {
    let err = ListenError::Closed;
    let display_str = format!("{}", err);
    assert_eq!(display_str, "announcer was dropped without announcing");
}

/// Test: Trait test: listen error timeout to string
///
/// Verifies: Verifies listen error timeout to string
/// Category: trait
#[test]
fn test_listen_error_timeout_to_string() {
    let err = ListenError::Timeout;
    assert_eq!(
        err.to_string(),
        "timeout elapsed while waiting for announcement"
    );
}

/// Test: Trait test: listen error closed to string
///
/// Verifies: Verifies listen error closed to string
/// Category: trait
#[test]
fn test_listen_error_closed_to_string() {
    let err = ListenError::Closed;
    assert_eq!(err.to_string(), "announcer was dropped without announcing");
}

/// Test: Trait test: listen error std error trait
///
/// Verifies: Verifies listen error std error trait
/// Category: trait
#[test]
fn test_listen_error_std_error_trait() {
    let err = ListenError::Timeout;
    // Verify it implements std::error::Error by using it as a trait object
    let _err_ref: &dyn Error = &err;
    // Verify source() returns None (default implementation)
    assert!(err.source().is_none());
}

/// Test: Trait test: listen error debug
///
/// Verifies: Verifies listen error debug
/// Category: trait
#[test]
fn test_listen_error_debug() {
    let timeout_err = ListenError::Timeout;
    let closed_err = ListenError::Closed;

    let timeout_debug = format!("{:?}", timeout_err);
    let closed_debug = format!("{:?}", closed_err);

    assert!(timeout_debug.contains("Timeout"));
    assert!(closed_debug.contains("Closed"));
}

// =============================================================================
// Clone and PartialEq Tests for Error Types
// =============================================================================

/// Test: Trait test: announce error clone
///
/// Verifies: Verifies announce error clone
/// Category: trait
#[test]
fn test_announce_error_clone() {
    let err1 = AnnounceError::AlreadyAnnounced(42);
    let err2 = err1.clone();
    assert_eq!(err1, err2);
}

/// Test: Trait test: announce error partial eq
///
/// Verifies: Verifies announce error partial eq
/// Category: trait
#[test]
fn test_announce_error_partial_eq() {
    let err1 = AnnounceError::AlreadyAnnounced(42);
    let err2 = AnnounceError::AlreadyAnnounced(42);
    let err3 = AnnounceError::AlreadyAnnounced(99);

    assert_eq!(err1, err2);
    assert_ne!(err1, err3);
}

/// Test: Trait test: listen error clone
///
/// Verifies: Verifies listen error clone
/// Category: trait
#[test]
fn test_listen_error_clone() {
    let err1 = ListenError::Timeout;
    let err2 = err1; // Copy trait is used here, not Clone
    assert_eq!(err1, err2);
}

/// Test: Trait test: listen error partial eq
///
/// Verifies: Verifies listen error partial eq
/// Category: trait
#[test]
fn test_listen_error_partial_eq() {
    let timeout1 = ListenError::Timeout;
    let timeout2 = ListenError::Timeout;
    let closed = ListenError::Closed;

    assert_eq!(timeout1, timeout2);
    assert_ne!(timeout1, closed);
}

// =============================================================================
// Error Usage in Result Context Tests
// =============================================================================

/// Test: Trait test: announce error in result
///
/// Verifies: Verifies announce error in result
/// Category: trait
#[test]
fn test_announce_error_in_result() {
    /// Test: Trait test: returns error
    ///
    /// Verifies: Verifies returns error
    /// Category: trait
    fn returns_error() -> Result<(), AnnounceError<i32>> {
        Err(AnnounceError::AlreadyAnnounced(42))
    }

    let result = returns_error();
    assert!(result.is_err());

    let err = result.unwrap_err();
    assert_eq!(format!("{}", err), "a value has already been announced");
}

/// Test: Trait test: listen error in result
///
/// Verifies: Verifies listen error in result
/// Category: trait
#[test]
fn test_listen_error_in_result() {
    /// Test: Trait test: returns timeout
    ///
    /// Verifies: Verifies returns timeout
    /// Category: trait
    fn returns_timeout() -> Result<i32, ListenError> {
        Err(ListenError::Timeout)
    }

    /// Test: Trait test: returns closed
    ///
    /// Verifies: Verifies returns closed
    /// Category: trait
    fn returns_closed() -> Result<i32, ListenError> {
        Err(ListenError::Closed)
    }

    let timeout_result = returns_timeout();
    assert!(timeout_result.is_err());
    assert_eq!(
        format!("{}", timeout_result.unwrap_err()),
        "timeout elapsed while waiting for announcement"
    );

    let closed_result = returns_closed();
    assert!(closed_result.is_err());
    assert_eq!(
        format!("{}", closed_result.unwrap_err()),
        "announcer was dropped without announcing"
    );
}

// =============================================================================
// Real-World Error Scenario Tests
// =============================================================================

/// Test: Trait test: listen error closed from dropped announcer
///
/// Verifies: Verifies listen error closed from dropped announcer
/// Category: trait
#[tokio::test]
async fn test_listen_error_closed_from_dropped_announcer() {
    let (announcer, announcement) = Announcement::<i32>::new();
    let listener = announcement.listener();

    // Drop announcer to trigger Closed error
    drop(announcer);

    let result = listener.listen().await;
    assert!(result.is_err());

    let err = result.unwrap_err();
    assert_eq!(err, ListenError::Closed);
    assert_eq!(
        format!("{}", err),
        "announcer was dropped without announcing"
    );

    // Verify Error trait methods
    assert!(err.source().is_none());
}

/// Test: Trait test: listen error timeout from timeout blocking
///
/// Verifies: Verifies listen error timeout from timeout blocking
/// Category: trait
#[cfg(feature = "std")]
#[test]
fn test_listen_error_timeout_from_timeout_blocking() {
    use std::time::Duration;

    let (_announcer, announcement) = Announcement::<i32>::new();
    let listener = announcement.listener();

    // Try to listen with a very short timeout (will timeout)
    let result = listener.listen_timeout_blocking(Duration::from_millis(1));
    assert!(result.is_err());

    let err = result.unwrap_err();
    assert_eq!(err, ListenError::Timeout);
    assert_eq!(
        format!("{}", err),
        "timeout elapsed while waiting for announcement"
    );

    // Verify Error trait methods
    assert!(err.source().is_none());
}

/// Test: Trait test: announce error into inner preserves value
///
/// Verifies: Verifies announce error into inner preserves value
/// Category: trait
#[test]
fn test_announce_error_into_inner_preserves_value() {
    let original_value = vec![1, 2, 3, 4, 5];
    let err = AnnounceError::AlreadyAnnounced(original_value.clone());

    let recovered_value = err.into_inner();
    assert_eq!(recovered_value, original_value);
}