additional testing for internal function

src/naive_datetime.rs

@@ -125,6 +125,8 @@ impl DateTime {
  })
  }
 
+ // FUTURE: is this actually worth it?
+ // shift by <48 hours, faster than going through date.shift()
  pub(crate) fn small_shift_unchecked(self, secs: i32) -> Self {
  debug_assert!(secs.abs() < S_PER_DAY * 2);
  let Self { date, time } = self;
@@ -925,4 +927,148 @@ mod tests {
  // invalid date
  assert_eq!(parse_date_and_time(b"2023-02-29 02:29:09.123456789"), None);
  }
+
+ #[test]
+ fn test_small_shift_unchecked() {
+ let d = DateTime {
+ date: Date {
+ year: 2023,
+ month: 3,
+ day: 2,
+ },
+ time: Time {
+ hour: 2,
+ minute: 9,
+ second: 9,
+ nanos: 0,
+ },
+ };
+ assert_eq!(d.small_shift_unchecked(0), d);
+ assert_eq!(
+ d.small_shift_unchecked(1),
+ DateTime {
+ date: Date {
+ year: 2023,
+ month: 3,
+ day: 2,
+ },
+ time: Time {
+ hour: 2,
+ minute: 9,
+ second: 10,
+ nanos: 0,
+ }
+ }
+ );
+ assert_eq!(
+ d.small_shift_unchecked(-1),
+ DateTime {
+ date: Date {
+ year: 2023,
+ month: 3,
+ day: 2,
+ },
+ time: Time {
+ hour: 2,
+ minute: 9,
+ second: 8,
+ nanos: 0,
+ }
+ }
+ );
+ assert_eq!(
+ d.small_shift_unchecked(S_PER_DAY),
+ DateTime {
+ date: Date {
+ year: 2023,
+ month: 3,
+ day: 3,
+ },
+ time: Time {
+ hour: 2,
+ minute: 9,
+ second: 9,
+ nanos: 0,
+ }
+ }
+ );
+ assert_eq!(
+ d.small_shift_unchecked(-S_PER_DAY),
+ DateTime {
+ date: Date {
+ year: 2023,
+ month: 3,
+ day: 1,
+ },
+ time: Time {
+ hour: 2,
+ minute: 9,
+ second: 9,
+ nanos: 0,
+ }
+ }
+ );
+ let midnight = DateTime {
+ date: Date {
+ year: 2023,
+ month: 3,
+ day: 2,
+ },
+ time: Time {
+ hour: 0,
+ minute: 0,
+ second: 0,
+ nanos: 0,
+ },
+ };
+ assert_eq!(midnight.small_shift_unchecked(0), midnight);
+ assert_eq!(
+ midnight.small_shift_unchecked(-1),
+ DateTime {
+ date: Date {
+ year: 2023,
+ month: 3,
+ day: 1,
+ },
+ time: Time {
+ hour: 23,
+ minute: 59,
+ second: 59,
+ nanos: 0,
+ }
+ }
+ );
+ assert_eq!(
+ midnight.small_shift_unchecked(-S_PER_DAY),
+ DateTime {
+ date: Date {
+ year: 2023,
+ month: 3,
+ day: 1,
+ },
+ time: Time {
+ hour: 0,
+ minute: 0,
+ second: 0,
+ nanos: 0,
+ }
+ }
+ );
+ assert_eq!(
+ midnight.small_shift_unchecked(-S_PER_DAY - 1),
+ DateTime {
+ date: Date {
+ year: 2023,
+ month: 2,
+ day: 28,
+ },
+ time: Time {
+ hour: 23,
+ minute: 59,
+ second: 59,
+ nanos: 0,
+ }
+ }
+ );
+ }
 }