#[cfg(test)]
mod tests{
    use assert_cmd::Command;
    use predicates::prelude::*;
    use std::fs;

    type TestResult = Result<(), Box<dyn std::error::Error>>;
    
    
    #[test]
    fn dies_no_args() -> TestResult {
        let mut cmd = Command::cargo_bin("xiuxiu-echor")?;
        cmd.assert().failure().stderr(predicate::str::contains("USAGE"));
        Ok(())
    }

    fn run(args: &[&str], expected_file: &str) -> TestResult {
        let expected = fs::read_to_string(expected_file)?;
        Command::cargo_bin("xiuxiu-echor")?
        .args(args)
        .assert()
        .success()
        .stdout(expected);
        Ok(())
    }
    
    #[test]
    fn runs(){
        let mut cmd = Command::cargo_bin("xiuxiu-echor").unwrap();
        cmd.arg("hello").assert().success();
    }

    #[test]
    fn hello1() -> TestResult {
        run(&["Hello there"], "tests/expected/hello1.txt")
    }

    #[test]
    fn hello2() -> TestResult{
        run(&["Hello", "there"], "tests/expected/hello2.txt")
    }

    #[test]
    fn hello1_no_newline() -> TestResult{
        run(&["Hello  there", "-n"], "tests/expected/hello1.n.txt")
    }

    #[test]
    fn hello2_no_newline() -> TestResult{
        run(&["-n", "Hello", "there"], "tests/expected/hello2.n.txt")
    }
}