CVS commit: src/tests/net/ndp

["Robert Elz" <kre%netbsd.org@localhost>]

Module Name:    src
Committed By:   kre
Date:           Sat Nov 25 07:58:47 UTC 2017

Modified Files:
        src/tests/net/ndp: t_ra.sh

Log Message:
Make this test somewhat deterministic - far fewer races, and most
of what are left are "race for the bus" type - if we lose, we just
wait for the next one ... slower but still reliable.

There are two exceptions ... when starting more than one rtadvd
(on different routers) we expect to receive an RA from each, but
all that we can check is that we received the (at least) right number
of RAs.  It is possible (though unlikely) that one router sent two
before another sent any, in which case we will not have the data we
expect, and a sub-test will fail.

Second, there is no way to know for sure that we have waited long
enough when we're waiting for data to expire - in systems with
correctly working clocks that actually measure time, this should not
be an issue, if data is due to expire in < 5 seconds, and we wait
5 seconds, and the data is still there, then that indicates a
failure, which should be detected.   Unfortunately with QEMU testing
time just isn't that reliable.  But fortunately, it is generally the
sleep which takes longer, while other timers run correctly, which is
the way that makes us happy...

While here lots of cleanups - everything from white space and
line wrapping, to removing superfluous quotes and adding some
(but probably not enough) that are not (though given the data is
all known here, lack of quotes will rarely hurt.)

Also take note of the fact that current rtadvd *cannot* delete its
pidfile, so waiting for that file to be removed is doomed to failure.
Do things in a way that works, rather than simply resorting to assassination.

Because we do a lot less "sleep and hope it is long enough" and more
"wait until it is observed to happen" the tests generally run in less
elapsed time than before (20% less has been observed.)  But because we
"wait until it is observed to happen" rather than just "sleep and hope
it is long enough" sometimes things take longer (and when that happens,
we no longer fail).  Up to 7% slower (overall) has been observed.
(Observations on an amd64 DomU, no idea yet as to what QEMU might observe.)


To generate a diff of this commit:
cvs rdiff -u -r1.31 -r1.32 src/tests/net/ndp/t_ra.sh

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.