An oft-used feature of gdb_test is that, if the message string is
supplied but empty (""), no PASS/FAIL output is produced. This is
used when you want to give a command to gdb without actually testing
anything.
It's very easy to implement the exact same behavior as gdb_test, but
are we certain that this is a valuable capability? Looking at the
documentation for that function, one can find:
# MESSAGE is an optional message to be printed. If this is
# omitted, then the pass/fail messages use the command string as the
# message. (If this is the empty string, then sometimes we don't
# call pass or fail at all; I don't understand this at all.)
The current implementation seems inconsistent; but also I don't think
that is really makes that much difference whether the test generates
a result or not.
But if that's what people want...