use mlua::{Error, ErrorContext, Lua, Result};

#[test]
fn test_error_context() -> Result<()> {
    let lua = Lua::new();

    let func = lua.create_function(|_, ()| {
        Err::<(), _>(Error::RuntimeError("runtime error".into())).context("some context")
    })?;
    lua.globals().set("func", func)?;

    let msg = lua
        .load("local _, err = pcall(func); return tostring(err)")
        .eval::<String>()?;
    assert!(msg.contains("some context"));
    assert!(msg.contains("runtime error"));

    let func2 = lua.create_function(|lua, ()| {
        lua.globals()
            .get::<_, String>("nonextant")
            .with_context(|_| "failed to find global")
    })?;
    lua.globals().set("func2", func2)?;

    let msg2 = lua
        .load("local _, err = pcall(func2); return tostring(err)")
        .eval::<String>()?;
    assert!(msg2.contains("failed to find global"));
    println!("{msg2}");
    assert!(msg2.contains("error converting Lua nil to String"));

    Ok(())
}