[v4] Fix strptime era handling, add more era tests [BZ #24394]

[TAMUKI Shoichi]

Hello DJ-san,

From: DJ Delorie <dj@redhat.com>
Subject: Re: [v4] Fix strptime era handling, add more era tests [BZ #24394]
Date: Fri, 29 Mar 2019 13:58:50 -0400

> > This test case is intended to check whether strptime can correctly
> > parse %EY, so it would be nice to rename it to tst-strptime4.c.
> 
> The test case was originally written to further test the strftime
> handling of the upcoming era change, but I don't care what the name of
> the test is ;-)
> 
> I added the strptime check "just because" and only found the strptime
> bug after that.
> 
> > The test case to check whether strftime can correctly format %EY
> > already exists as tst-strftime2.c.
> 
> Yup, this is an additional test.
> 
> I see no harm in having overlapping test coverage, especially if the
> tests approach the problem in different ways.  New coverage can be added
> to whichever test the submitter finds more comfortable editing, too.
> Personally, I'm not a fan of logic-driven test data.  I prefer
> table-driven since I don't need to worry as much about bugs in the test
> itself, and it's easier to list unusual test cases than try to encode
> them in logic.

OK.  I agree to keep the test suite named tst-strftime3.c.

Regards,
TAMUKI Shoichi