Missing tests

[Rich Felker <dalias@libc.org>]

Here are some things that don't seem to be tested that would be nice
to get added to the test suite (http://nsz.repo.hu/git/?p=libc-test)

- Interpretation of POSIX TZ strings
- Daylight time transition tests with zoneinfo and POSIX zones
- Lots of corner cases for strftime and strptime
- Regression test for recent pthread_once race (hard to catch)
- Sanity-checking ucontext_t layout via signal handlers
- Alternate signal stacks
- Basic sanity checks for most syscalls
- Checks for various subtle stdio behavior:
  - File position on exit
  - Interactions of ungetc and file position
  - Append mode file positions

It might make sense to make a new tree separate from functional for
tests that don't really check the functionality of the interface but
just whether it's present and "doing something". Some existing tests
might be candidates for moving there too..?

Rich


P.S. I started writing this email quite a while back when I had
connectivity problems and never got around to finishing/sending it, so
some of it is motivated by discussions that were going on at the time.
:-)