Not only is this a slightly more logical name, but it allows us to expose the verbose flag, previously private to cryb_t_main.c, as the equally logically named t_verbose.
These tests reveal that both functions assume that the target is initially positive zero if it is not identical with one of the operands, and fail in various ways if it is not, or if it is uninitialized.
Unlike assert(3), which uses abort(3), this has no other side effects (before raising SIGABRT) than an fprintf() call. The test framework will catch the SIGABRT, report that the test case failed, and proceed with the next case.
All further instances of asprintf() or vasprintf() in our codebase are either in libcryb-test or in individual unit tests, and in all cases, the only consequence of a failed call is that the result will say "no description" instead of either a description of the test or an explanation of how it failed. Therefore, we can simply ignore the problem and cast the call to void to satisfy gcc.
POSIX requires <stdio.h> and <unistd.h> to define off_t and ssize_t like <sys/types.h> does, but not all platforms respect that. Play it safe by always including <sys/types.h>.
Instead of having libcryb-test provide main() and assume that the test program defines t_prepare() and t_cleanup(), have libcryb-test provide a t_main() function which the test program calls with pointers to its prepare and cleanup functions.
- Set t_malloc_fatal so we don't have to check for allocation failures
(the driver will catch the SIGABRT).
- Use string_dup_cs() instead of string_new() + string_append_cs().
allocation failures which are either harmless (e.g. failing to allocate
the test description string) or will trigger a segfault which the driver
now catches, allowing subequent test cases to run.
Add several subtraction test cases and modify some others to better
exercise the carry logic, which is far more complex for subtraction than
for addition.
Add test cases where the target is the same MPI as one or both operands.
