[PATCH] add tests for tzset(3)

[jdoubleu]

Hi Dimitar,

On 4/10/2022 10:43 AM, Dimitar Dimitrov wrote:
> I get the following failure on pru-none-elf and arm-none-eabi targets:

that is interesting! I just checked and they are still passing on 
x86_64-pc-linux-gnu. Which begs the question: What is the difference to 
your environment/target platform?

Are you using any additional compilation flags? Have you 
enabled/disabled optimizations? Have you enabled the nano I/O API[1]?
What compiler (and version) are you using? How/Where are you running the 
tests?

> [..] timezone = "<+0123456789ABCDEF>3:33:33"

The given test case aims to check for tzset's parsing behavior when the 
name (inside the angle brackets) exceeds the TZNAME_MAX var, i.e. is too 
long to be fully stored. The default behavior is to truncate the name 
and ignore all remaining chars[2]. The time should still be parsed.

> Assertion failed! Expected 1647906533 to equal 1647916532.

Now, the interesting part is, that the diff is 9,999 seconds. The time 
is off by 6 hours, 20 minutes and 12 seconds. That is 2 hours, 46 
minutes and 38 seconds too far in the future. I am not sure where this 
is coming from.

Neither does it look like it bailed early[3], because it couldn't parse 
the name.

Please try and remove the "<+0123456789ABCDEF>" part from the string in 
the tests[4] and re-run the tests.

Could you maybe also post the assembly listing and intermediate output 
of the compiler? If you're using gcc, just (re)configure newlib and 
rebuild libc:

	CFLAGS=-save-temps=obj ../newlib/configure
	make clean # get rid of stamp files
	make

then copy and attach the following files:
	
	libc/time/libc_a-tzset_r.i
	libc/time/libc_a-tzset_r.s


[1]: 
https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=newlib/README;h=97890b9d20ca0ac9f206d7a2334d55a3d7052289;hb=HEAD#l403
[2]: https://sourceware.org/pipermail/newlib/2022/019535.html
[3]: 
https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=newlib/libc/time/tzset_r.c;h=9cb30b188f989f65ec9eb6417f5d74020f8c72e9;hb=HEAD#l57
[4]: 
https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=newlib/testsuite/newlib.time/tzset.c;h=0e5b196c629bcbecae6148c09bbeba82079c5367;hb=HEAD#l96


Cheers
---
🙎🏻‍♂️ jdoubleu