[phobos] windows tz updates breaking unit tests, again

[Jonathan M Davis via phobos]

On Wednesday, April 13, 2016 21:03:45 Vladimir Panteleev via phobos wrote:
> On Wednesday, 13 April 2016 at 18:50:31 UTC, Brad Roberts wrote:
> > https://support.microsoft.com/en-us/kb/3148851
> >
> > This update floated through last night and is now causing the
> > Win_32 tester to fail.  The Win_32_64 will almost certainly
> > start failing as soon as the update makes its way onto that box.
>
> Took a stab at it:
> https://github.com/D-Programming-Language/phobos/pull/4196
>
> > Why are the datetime tests so damned sensitive to external
> > system state?
>
> Seems like the tests want to make sure that we know how to
> convert ALL Windows timezone names to their tz database
> equivalents. Not sure how much sense that makes, however the
> relevant functions are being deprecated.

If we don't test it, we won't catch when the code is wrong due to a change
in Microsoft's time zone info. But the fact that it changes so frequently
like this is precisely why that functionality has been deprecated in favor
of reading the conversion data in from a file, thereby leaving it up to the
programmer to make sure that the data is up-to-date. I think that it's quite
clear that hardcoding it as I did originally has proven to be a bad idea.
Unfortunately, it'll be a while before those functions are done with the
deprecation cycle and removed, so we have to continue to deal with
Microsoft's random changes until then.

- Jonathan M Davis