Don't skip crons when time jumps fwd due to DST

Author: rdingwall

spec.go

@@ -140,8 +140,16 @@ WRAP:
 			added = true
 			t = time.Date(t.Year(), t.Month(), t.Day(), t.Hour(), 0, 0, 0, loc)
 		}
+		prev := t
 		t = t.Add(1 * time.Hour)
-
+		// ISC cron behavior: If time was adjusted one hour forward, those jobs
+		// that would have run in the interval that has been skipped will be run
+		// immediately.
+		if t.Hour()-prev.Hour() == 2 {
+			if 1<<uint(t.Hour()-1)&s.Hour > 0 {
+				break
+			}
+		}
 		if t.Hour() == 0 {
 			goto WRAP
 		}

spec_test.go

@@ -111,7 +111,7 @@ func TestNext(t *testing.T) {
 		{"Mon Jul 9 23:35 2012", "0 0 0 29 Feb ?", "Mon Feb 29 00:00 2016"},
 
 		// Daylight savings time 2am EST (-5) -> 3am EDT (-4)
-		{"2012-03-11T00:00:00-0500", "TZ=America/New_York 0 30 2 11 Mar ?", "2013-03-11T02:30:00-0400"},
+		{"2012-03-11T00:00:00-0500", "TZ=America/New_York 0 30 2 11 Mar ?", "2012-03-11T03:30:00-0400"},
 
 		// hourly job
 		{"2012-03-11T00:00:00-0500", "TZ=America/New_York 0 0 * * * ?", "2012-03-11T01:00:00-0500"},
@@ -129,8 +129,8 @@ func TestNext(t *testing.T) {
 		{"2012-03-11T00:00:00-0500", "TZ=America/New_York 0 0 1 * * ?", "2012-03-11T01:00:00-0500"},
 		{"2012-03-11T01:00:00-0500", "TZ=America/New_York 0 0 1 * * ?", "2012-03-12T01:00:00-0400"},
 
-		// 2am nightly job (skipped)
-		{"2012-03-11T00:00:00-0500", "TZ=America/New_York 0 0 2 * * ?", "2012-03-12T02:00:00-0400"},
+		// Daylight savings time 2am EST (-5) -> 3am EDT (-4)
+		{"2012-03-11T00:00:00-0500", "TZ=America/New_York 0 0 2 * * ?", "2012-03-11T03:00:00-0400"},
 
 		// Daylight savings time 2am EDT (-4) => 1am EST (-5)
 		{"2012-11-04T00:00:00-0400", "TZ=America/New_York 0 30 2 04 Nov ?", "2012-11-04T02:30:00-0500"},