AILang/crates/ail/tests/show_print_e2e.rs

//! End-to-end tests for the `print` polymorphic helper shipped in
//! milestone 24.3.
//!
//! Each test compiles a `.ail.json` workspace via the `ail build`
//! subcommand, runs the resulting native binary, and asserts on stdout.
//!
//! Properties protected:
//! - `print_primitives_smoke_runs_end_to_end`: `print` at four primitive
//!   types (Int / Bool / Str / Float) emits the expected textual
//!   representation of each value via the prelude Show instances +
//!   `io/print_str`. The four `print__T` mono symbols synthesise from
//!   the prelude `instance prelude.Show T` bodies and route through the
//!   corresponding `<T>_to_str` runtime primitive.
//! - `print_user_adt_runs_end_to_end`: `print` composes with a
//!   user-declared `instance prelude.Show IntBox` to emit a user-ADT's
//!   structural representation. Confirms that the post-mono synthesised
//!   `print__<UserType>` body's nested `show x` call rewrites to the
//!   user instance's `show__<UserType>` mono symbol and that the
//!   cross-module reference from `prelude.print__<UserType>` to
//!   `<user_module>.show__<UserType>` lowers cleanly through codegen.

use std::path::PathBuf;
use std::process::Command;

fn fixture_path(name: &str) -> PathBuf {
    PathBuf::from(env!("CARGO_MANIFEST_DIR"))
        .join("../../examples")
        .join(name)
}

fn build_and_run(fixture: &str) -> String {
    let src = fixture_path(fixture);
    let out = std::env::temp_dir().join(format!("ail_{}.bin", fixture.replace('.', "_")));

    let build = Command::new(env!("CARGO_BIN_EXE_ail"))
        .args(["build", src.to_str().unwrap(), "-o", out.to_str().unwrap()])
        .output()
        .expect("ail build");
    assert!(
        build.status.success(),
        "ail build failed for {fixture}:\nstdout: {}\nstderr: {}",
        String::from_utf8_lossy(&build.stdout),
        String::from_utf8_lossy(&build.stderr),
    );

    let run = Command::new(&out).output().expect("run binary");
    assert!(
        run.status.success(),
        "binary exited non-zero:\nstdout: {}\nstderr: {}",
        String::from_utf8_lossy(&run.stdout),
        String::from_utf8_lossy(&run.stderr),
    );
    String::from_utf8_lossy(&run.stdout).trim().to_string()
}

#[test]
fn print_primitives_smoke_runs_end_to_end() {
    let stdout = build_and_run("show_print_smoke.ail");
    // print 42        → "42\n"   (int_to_str + puts)
    // print true      → "true\n" (bool_to_str + puts)
    // print "hello"   → "hello\n" (str_clone + puts)
    // print 3.14      → "3.14\n" (float_to_str / libc %g + puts)
    // puts emits each Str + a trailing newline; trimmed output is
    // "42\ntrue\nhello\n3.14".
    assert_eq!(stdout, "42\ntrue\nhello\n3.14", "got: {stdout:?}");
}

#[test]
fn print_user_adt_runs_end_to_end() {
    let stdout = build_and_run("show_user_adt.ail");
    // print (MkIntBox 7) → "7\n" (via user instance prelude.Show
    // IntBox that unwraps via match + int_to_str).
    assert_eq!(stdout, "7", "got: {stdout:?}");
}