//! This file will run at build time to autogenerate the Emscripten tests
//! It will compile the files indicated in TESTS, to:executable and .wasm
//! - Compile using cc and get the output from it (expected output)
//! - Compile using emcc and get the .wasm from it (wasm)
//! - Generate the test that will compare the output of running the .wasm file
//!   with wasmer with the expected output
use std::env;
use std::fs;
use std::path::PathBuf;

static BANNER: &str = "// Rust test file autogenerated with cargo build (build/emtests.rs).
// Please do NOT modify it by hand, as it will be reseted on next build.\n";

const TESTS: [&str; 1] = [
    "emtests/localtime.c"
];


pub fn build() {
    let rust_test_modpath = concat!(env!("CARGO_MANIFEST_DIR"), "/src/emtests/mod.rs");

    let mut modules: Vec<String> = Vec::new();
    // modules.reserve_exact(TESTS.len());

    modules.insert(0, BANNER.to_string());
    // We add an empty line
    modules.push("".to_string());

    let modfile: String = modules.join("\n");
    let source = fs::read(&rust_test_modpath).unwrap();
    // We only modify the mod file if has changed
    if source != modfile.as_bytes() {
        fs::write(&rust_test_modpath, modfile.as_bytes()).unwrap();
    }
}