The test process like that:
- run long dns refresh process
- request for the resolve hostname with short abort_source timer - result
should be empty list, because of aborted request
The test sometimes finishes long dns refresh before abort_source fired and the
result list is not empty.
There are two issues. First, as.reset() changes the abort_source timeout. The
patch adds a get() method to the abort_source_timeout class, so there is no
change in the abort_source timeout. Second, a sleep could be not reliable. The
patch changes the long sleep inside a dns refresh lambda into
condition_variable handling, to properly signal the end of the dns refresh
process.
Fixes: #26561
Fixes: VECTOR-268
It needs to be backported to 2025.4
Closesscylladb/scylladb#26566
(cherry picked from commit 10208c83ca)
Closesscylladb/scylladb#26598