as-rust/tests/sub_task_test.rs

use std::process::{Command, Stdio};
use std::io::{self, Read};

#[tokio::test]
async fn test_sub_task() -> io::Result<()> {
    let mut child = Command::new("cmd.exe")
        .arg("/c")
        .arg("echo Hello, world!")
        .stdout(Stdio::piped())
        .spawn()?;

    let mut output = String::new();
    if let Some(ref mut stdout) = child.stdout {
        stdout.read_to_string(&mut output)?;
    }

    println!("{}", output);

    Ok(())
}