pytest changes the test's sys.stdout and sys.stderr to the
captured fds when it captures the outputs of the test. so we
are not able to get the STDOUT_FILENO and STDERR_FILENO in C
by querying `sys.stdout.fileno()` and `sys.stderr.fileno()`.
their return values are not 1 and 2 anymore, unless pytest
is started with "-s".
so, to ensure that we always redirect the child process's
outputs to the log file. we need to use 1 and 2 for accessing
the well-known fds, which are the ones used by the child
process, when it writes to stdout and stderr.
this change should address the problem that the log file is
always empty, unless "-s" is specified.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#15560
f69a44bb37