Invoked once per task.
the concatenated stream from stdin, stripped of the PASS or FAIL tokens from BatchProcessOptions.
stdin
PASS
FAIL
BatchProcessOptions
if defined, includes all text emitted to stderr.
true iff the PASS pattern was found in stdout.
true
an error if the Parser implementation wants to reject the task. It is valid to raise Errors if stderr is undefined.
Invoked once per task.