This commit add 4 tests for the new option:
1. Test default configuration of stale-answer-client-timeout, a
value of 1.8 seconds, with stale-refresh-time disabled.
2. Test disabling of stale-answer-client-timeout.
3. Test stale-answer-client-timeout with a value of zero, in this
case we take advantage of a log entry which shows that a stale
answer was promptly used before an attempt to refresh the RRset
is made. We also check, by activating a disabled authoritative
server, that the RRset was successfully refreshed after that.
4. Test stale-answer-client-timeout 0 with stale-refresh-time 4, in
this test we want to ensure a couple things:
- If we have a stale RRSet entry in cache, a request must be
promptly answered with this data, while BIND must also attempt
to refresh the RRSet in background.
- If the attempt to refresh the RRSet times out, the RRSet must
have its stale-refresh-time window activated.
- If a new request for the same RRSet arrives, it must be
promptly answered with stale data due to stale-refresh-time
being active for this RRSet, in this case no attempt to refresh
the RRSet is made.
- Enable authoritative server, ensure that the RRSet was not
refreshed, to honor stale-refresh-time.
- Wait for stale-refresh-window time pass, send another request
for the same RRSet, this time we expect the answer to be the
stale entry in cache being hit due to
stale-answer-client-timeout 0.
- Send another request, this time we expect the answer to be an
active RRSet, since it must have been refreshed during the
previous request.
(cherry picked from commit 35fd039d03)
bea63000db