pub fn format_timestamp(ms: u64) -> String {
let hours = ms / 3_600_000;
let minutes = (ms % 3_600_000) / 60_000;
let seconds = (ms % 60_000) / 1_000;
let millis = ms % 1_000;
format!("{hours:02}:{minutes:02}:{seconds:02},{millis:03}")
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn formats_zero() {
assert_eq!(format_timestamp(0), "00:00:00,000");
}
#[test]
fn formats_with_millis() {
assert_eq!(format_timestamp(1_234), "00:00:01,234");
}
#[test]
fn formats_long_duration() {
assert_eq!(format_timestamp(3_661_500), "01:01:01,500");
}
}