Merge "PDL: let ‘find_binary’ helper return a ‘Result’"

/// Search for a binary in `$PATH` or as a sibling to the current

/// executable (typically the test binary).

fn find_binary(name: &str) -> Option<std::path::PathBuf> {

fn find_binary(name: &str) -> Result<std::path::PathBuf, String> {

    let mut current_exe = std::env::current_exe().unwrap();

    current_exe.pop();

    let paths = std::env::var_os("PATH").unwrap();

    for mut path in std::iter::once(current_exe).chain(std::env::split_paths(&paths)) {

    for mut path in std::iter::once(current_exe.clone()).chain(std::env::split_paths(&paths)) {

        path.push(name);

        if path.exists() {

            return Some(path);

            return Ok(path);

        }

    }

    None

    Err(format!(

        "could not find '{}' in the directory of the binary ({}) or in $PATH ({})",

        name,

        current_exe.to_string_lossy(),

        paths.to_string_lossy(),

    ))

}

/// Parse a string fragment as a PDL file.