snprintf will only truncate the output if the data its given
is corrupted, but a truncated buffer will not match the
"pristine" data's buffer, which is all we need. So just
disable the warning via the DIAG macros.
Test the transition points between all the currently listed Japanese
era name changes. This includes testing the transition between the
first year date and the second year date. This test will help test
the upcoming Japanese era name change.
Also fixes a fencepost error where the era name isn't properly parsed
by strptime in the last (partial) year of the era.
Example: if an era change happens in Feb 1990, and again in Aug 1995,
that's 5.5 years long, but the 0.5 year wasn't accounted for.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>