import os
import time

const vexe = @VEXE
const vroot = os.dir(vexe)
const tdir = os.join_path(os.vtmp_dir(), 'vwatch_test_24571')
const tsource_dir = os.join_path(tdir, 'src')
const toutput_dir = os.join_path(tdir, 'out')

fn testsuite_begin() {
    os.rmdir_all(tdir) or {}
    os.mkdir_all(tsource_dir)!
    os.mkdir_all(toutput_dir)!
}

fn testsuite_end() {
    os.rmdir_all(tdir) or {}
}

fn test_watch_keeps_backend_flag_intact() {
    source_path := os.join_path(tsource_dir, 'hello.v')
    output_path := os.join_path(toutput_dir, 'hello.js')
    os.write_file(source_path, "fn main() {\n\tprintln('Hello world')\n}\n")!

    mut process := os.new_process(vexe)
    process.set_work_folder(vroot)
    process.set_redirect_stdio()
    process.use_pgroup = true
    process.set_args(['watch', '-backend', 'js_browser', '-output', output_path, source_path])
    process.run()

    for _ in 0 .. 300 {
        if os.exists(output_path) || !process.is_alive() {
            break
        }
        time.sleep(100 * time.millisecond)
    }
    if process.is_alive() {
        process.signal_pgkill()
    }
    process.wait()
    output := process.stdout_slurp() + process.stderr_slurp()
    process.close()

    assert os.exists(output_path), output
    assert output.contains(' -backend js_browser '), output
    assert !output.contains('-baend'), output
    assert !output.contains('Unknown argument `-baend`'), output
}