golang timezone daylight savings time doesn't work

I know that on 26 Oct, 2014 02:00am the clock should go backwards 1 hour, but I can't reproduce this using a simple golang program

const timeFormat = "2 Jan, 2006 3:04pm"

loc, err := time.LoadLocation("Europe/Moscow")
log.Print(loc, err)

testz , _ := time.ParseInLocation( timeFormat, "26 Oct, 2014 01:59am",  loc)
fmt.Println( testz , testz.UTC())
testz = testz.Add( time.Minute )
fmt.Println( testz , testz.UTC())
testz = testz.Add( time.Minute )
fmt.Println( testz , testz.UTC())

outputs

2014-10-26 01:59:00 +0300 MSK 2014-10-25 22:59:00 +0000 UTC
2014-10-26 02:00:00 +0300 MSK 2014-10-25 23:00:00 +0000 UTC
2014-10-26 02:01:00 +0300 MSK 2014-10-25 23:01:00 +0000 UTC

go 1.6, linux

Given your output, it looks like this line:

testz , _ := time.ParseInLocation(timeFormat, "26 Oct, 2014 01:59am", loc)

... is actually giving you the later of the two occurrences of 1:59am, given that it's showing an offset of +3. In other words, you're looking at three minutes of time an hour later than you want to be - starting nearly an hour after the daylight saving transition.

You can change your code to start with an unambiguous value like this:

testz, _ := time.ParseInLocation(timeFormat, "26 Oct, 2014 00:59am", loc)
testz = testz.Add(time.Hour)

I'd expect that to then show

2014-10-26 01:59:00 +0400 MSK 2014-10-25 21:59:00 +0000 UTC
2014-10-26 01:00:00 +0300 MSK 2014-10-25 22:00:00 +0000 UTC
2014-10-26 01:01:00 +0300 MSK 2014-10-25 22:01:00 +0000 UTC

(I haven't tried this, as I don't have Go installed - but I'd expect it to work.)

It's not because your code has error,just for time.UTC() will print UTC time,that is timezone 0 time,and from your code time.LoadLocation("Europe/Moscow") we can know maybe you are in Moscow,which belongs to east timezone 3,so the time will be earlier than utc time by three hours,meaning that <your time>=<utc time>+3.