Wolfgang Walther <walther(at)technowledgy(dot)de> writes:
> The core regression tests need to be run with a timezone that tests
> special cases in the timezone handling code. But that might not be true
> for extensions - all they want could be a stable output across major and
> minor versions of postgres and versions of tzdata. It could be helpful
> to set pg_regress' timezone to UTC, for example?
I would not recommend that choice. It would mask simple errors such
as failing to apply the correct conversion between timestamptz and
timestamp values. Also, if you have test cases that are affected by
this issue at all, you probably have a need/desire to test things like
DST transitions.
regards, tom lane