Function lilypond::is_lilypond_file

pub fn is_lilypond_file(filename: &'static str) -> bool

Checks if file has .ly extension

Usage:

use lilypond::is_lilypond_file;

let valid = "test.ly";
let invalid = "test.png";
// Create valid file
fsutils::create_file(valid);
// Create invalid file
fsutils::create_file(invalid);

assert_eq!(is_lilypond_file(valid), true);
assert_eq!(is_lilypond_file(invalid), false);
// Will also return false if file does not exist
assert_eq!(is_lilypond_file("does_not_exit.txt"), false);

// Clean up
fsutils::rm(valid);
fsutils::rm(invalid);