mae 0.3.14

use std::panic::Location;

/// Trait for safe test assertions on `Option` and `Result`.
pub trait Must<T> {
    /// Panics if the value is not as expected, with caller location.
    #[track_caller]
    fn must(self) -> T;
}

pub trait MustExpect<T>: Sized {
    /// Like `expect`, but includes caller location in the panic message.
    #[track_caller]
    fn must_expect(self, msg: &str) -> T;
}

impl<T> Must<T> for Option<T> {
    #[track_caller]
    fn must(self) -> T {
        self.unwrap_or_else(|| {
            panic!("test invariant failed: expected Some, got None at {}", Location::caller())
        })
    }
}

impl<T> MustExpect<T> for Option<T> {
    #[track_caller]
    fn must_expect(self, msg: &str) -> T {
        self.unwrap_or_else(|| {
            panic!("{} (expected Some, got None) at {}", msg, Location::caller())
        })
    }
}

impl<T, E: std::fmt::Debug> Must<T> for Result<T, E> {
    #[track_caller]
    fn must(self) -> T {
        self.unwrap_or_else(|err| {
            panic!("test invariant failed: expected Ok, got {:?} at {}", err, Location::caller())
        })
    }
}

impl<T, E: std::fmt::Debug> MustExpect<T> for Result<T, E> {
    #[track_caller]
    fn must_expect(self, msg: &str) -> T {
        self.unwrap_or_else(|err| {
            panic!("{} (expected Ok, got {:?}) at {}", msg, err, Location::caller())
        })
    }
}

// ── Convenience free functions ──────────────────────────────────────────────

#[track_caller]
pub fn must_be_some<T>(opt: Option<T>) -> T {
    opt.must()
}

#[track_caller]
pub fn must_be_ok<T, E: std::fmt::Debug>(res: Result<T, E>) -> T {
    res.must()
}

#[track_caller]
pub fn must_expect_some<T>(opt: Option<T>, msg: &str) -> T {
    opt.must_expect(msg)
}

#[track_caller]
pub fn must_expect_ok<T, E: std::fmt::Debug>(res: Result<T, E>, msg: &str) -> T {
    res.must_expect(msg)
}

#[allow(clippy::disallowed_methods)]
#[track_caller]
pub fn must_eq<V: PartialEq + std::fmt::Debug>(left: V, right: V) {
    assert_eq!(left, right);
}

#[track_caller]
pub fn must_ne<V: PartialEq + std::fmt::Debug>(left: V, right: V) {
    assert_ne!(left, right);
}

#[track_caller]
pub fn must_be_true(b: bool) {
    assert!(b,);
}

/// Returns `true` when `MAE_TESTCONTAINERS` env var is set to `1` or `true`.
pub fn testcontainers_enabled() -> bool {
    std::env::var("MAE_TESTCONTAINERS")
        .map(|v| v == "1" || v.eq_ignore_ascii_case("true"))
        .unwrap_or(false)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn option_must_some_ok() {
        let v = Some(42).must();
        must_eq(v, 42);
    }

    #[test]
    #[should_panic(expected = "expected Some, got None")]
    fn option_must_none_panics() {
        let _: i32 = None.must();
    }

    #[test]
    fn option_must_expect_ok() {
        let v = Some("hello").must_expect("should have value");
        must_eq(v, "hello");
    }

    #[test]
    #[should_panic(expected = "custom msg")]
    fn option_must_expect_panics_with_msg() {
        let _: i32 = None.must_expect("custom msg");
    }

    #[test]
    fn result_must_ok() {
        let v: i32 = Ok::<i32, &str>(7).must();
        must_eq(v, 7);
    }

    #[test]
    #[should_panic(expected = "expected Ok")]
    fn result_must_err_panics() {
        let r: Result<i32, &str> = Err("boom");
        let _ = r.must();
    }

    #[test]
    fn result_must_expect_ok() {
        let v: &str = Ok::<&str, &str>("yes").must_expect("should succeed");
        must_eq(v, "yes");
    }

    #[test]
    #[should_panic(expected = "should fail")]
    fn result_must_expect_panics_with_msg() {
        let r: Result<i32, &str> = Err("nope");
        let _ = r.must_expect("should fail");
    }

    #[test]
    fn free_helpers_work() {
        let a = must_be_some(Some(1));
        let b = must_be_ok::<_, &str>(Ok::<i32, &str>(2));
        let c = must_expect_some(Some(3), "msg");
        let d = must_expect_ok::<_, &str>(Ok::<i32, &str>(4), "msg");

        must_eq(a + b + c + d, 10);
    }

    #[test]
    fn must_eq_and_ne() {
        must_eq(5, 5);
        must_ne(5, 6);
    }

    #[test]
    fn must_be_true_works() {
        must_be_true(true);
    }

    #[test]
    #[should_panic]
    fn must_be_true_panics_on_false() {
        must_be_true(false);
    }
}