libc tests based on libc-testsuit by Rich Felker

see http://git.musl-libc.org/cgit

configure tests:

	cp dist/config.mak .

	# edit config.mak

build tests:

	make

run tests:

	make run

design goals:

- tests should be easy to run even a single test in isolation

(so test should be self contained if possible)

- failure of one test should not interfere with others

(build failure, crash or unexpected results are all failures)

- test output should point to the cause of failure

- test results should be robust

- the test system should have minimal dependency

(libc, posix sh, gnu make)

- the test system should run on all archs and libcs

- tests should leave the system in a clean state

framework:

the convention is that each test is in a separate file

at a path like src/directory/file.c with its own main

the test should return 0 on success and non-0 on failure

error messages relevant to the test system should be

printed to standard out (fd 1)

src/functional/test.h usage:

use error in tests when possible instead of printf

(error truncates the formatted string to 512 bytes and uses a

single write call to output it to fd 1, terminating the error

string with a \n is the responsibility of the caller)

and return test_status from main (set by error, 0 by default)

when many similar checks are done, helper macros can be used like

#define T1(a,b) (check(a,b) || (error("check(%s,%s) failed\n", a, b),0))

#define T2(f,w) (result=(f), result==(w) || (error("%s failed: got %s, want %s\n", #f, result, w),0))

a simple example:

#include "test.h"

#define T(c,...) ((c) || (error(#c " failed: " __VA_ARGS__),0))

int main(void)

{

	T('a'+1=='b', "'a'==%d 'b'==%d\n", 'a', 'b');

	T(-5%3==-2, "bad mod semantics\n");

	return test_status;

}