Merge pull request #323 from cardigan1008/issue-244-14

Fix ceil with zero duration

src/duration/mod.rs

@@ -538,9 +538,11 @@ impl Duration {
     /// assert_eq!(two_hours_three_min.floor(1.hours() + 5.minutes()), 1.hours() + 5.minutes());
     /// ```
     pub fn floor(&self, duration: Self) -> Self {
-        Self::from_total_nanoseconds(
-            self.total_nanoseconds() - self.total_nanoseconds() % duration.total_nanoseconds(),
-        )
+        Self::from_total_nanoseconds(if duration.total_nanoseconds() == 0 {
+            0
+        } else {
+            self.total_nanoseconds() - self.total_nanoseconds() % duration.total_nanoseconds()
+        })
     }
 
     /// Ceils this duration to the closest provided duration

tests/duration.rs

@@ -577,3 +577,15 @@ fn test_min_max() {
     assert_eq!(d1, d1.max(d0));
     assert_eq!(d1, d0.max(d1));
 }
+
+#[test]
+fn regression_test_gh_244() {
+    let zero = Duration::ZERO;
+    // Test that the ceil of a zero duration is still zero.
+    assert_eq!(zero.ceil(zero), zero);
+    let non_zero = Duration::from_parts(1, 23456);
+    // Test that the ceil of a non-zero duration by zero is still zero.
+    assert_eq!(non_zero.ceil(zero), zero);
+    // Test that the ceil of a zero duration by a non-zero is non-zero duration.
+    assert_eq!(zero.ceil(non_zero), non_zero);
+}