daemonize 0.0.2

Library to enable your code run as a daemon process on Unix-like systems.
Documentation 
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extern crate tempdir;
extern crate libc;

use std::io::prelude::*;
use std::ffi::{OsStr};

use tempdir::{TempDir};

fn run<'a, S: AsRef<OsStr>>(cmd: S, args: &[S]) -> u32 {
    let mut cmd = std::process::Command::new(cmd);
    for arg in args {
        cmd.arg(arg);
    }
    let mut child = cmd.spawn().unwrap();
    let pid = child.id();
    child.wait().unwrap();

    std::thread::sleep(std::time::Duration::from_millis(100));
    pid
}

#[test]
fn test_chdir() {
    let tmpdir = TempDir::new("chdir").unwrap();

    let args = vec![tmpdir.path().to_str().unwrap(), "test"];
    run("target/debug/examples/test_chdir", &args);

    let mut data = Vec::new();
    std::fs::File::open(tmpdir.path().join("test")).unwrap().read_to_end(&mut data).unwrap();
    assert!(data == b"test")
}

#[test]
fn test_pid() {
    let tmpdir = TempDir::new("chdir").unwrap();
    let pid_file = tmpdir.path().join("pid");

    let args = vec![pid_file.to_str().unwrap()];
    let child_pid = run("target/debug/examples/test_pid", &args);

    let mut data = String::new();
    std::fs::File::open(&pid_file).unwrap().read_to_string(&mut data).unwrap();
    let pid: u32 = data.parse().unwrap();
    assert!(pid != child_pid)
}

#[test]
fn double_run() {
    let tmpdir = TempDir::new("double_run").unwrap();
    let pid_file = tmpdir.path().join("pid");
    let first_result = tmpdir.path().join("first");
    let second_result = tmpdir.path().join("second");

    for file in vec![&first_result, &second_result] {
        let args = vec![pid_file.to_str().unwrap(), file.to_str().unwrap()];
        run("target/debug/examples/test_double_run", &args);
    }
    std::thread::sleep(std::time::Duration::from_millis(100));

    {
        let mut data = String::new();
        std::fs::File::open(&first_result).unwrap().read_to_string(&mut data).unwrap();
        assert!(data == "ok")
    }

    {
        let mut data = String::new();
        std::fs::File::open(&second_result).unwrap().read_to_string(&mut data).unwrap();
        assert!(data == "error")
    }
}

#[test]
#[cfg(target_os = "macos")]
fn test_uid_gid() {
    let tmpdir = TempDir::new("uid_gid").unwrap();
    let result_file = tmpdir.path().join("result");

    let args = vec!["nobody", "daemon", &result_file.to_str().unwrap()];
    run("target/debug/examples/test_uid_gid", &args);

    let own_uid_gid_string = unsafe { format!("{} {}", libc::getuid(), libc::getgid()) };

    let mut data = String::new();
    std::fs::File::open(&result_file).unwrap().read_to_string(&mut data).unwrap();
    assert!(!data.is_empty());
    assert!(data != own_uid_gid_string)
}