[tor-bugs] #26105 [Core Tor/Tor]: Perhaps, make test coverage deterministic _within_ lines

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#26105: Perhaps, make test coverage deterministic _within_ lines
------------------------------+------------------------------------------
     Reporter:  nickm         |      Owner:  (none)
         Type:  defect        |     Status:  new
     Priority:  Low           |  Milestone:  Tor: unspecified
    Component:  Core Tor/Tor  |    Version:
     Severity:  Normal        |   Keywords:  coverage, tests, determinism
Actual Points:                |  Parent ID:
       Points:                |   Reviewer:
      Sponsor:                |
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 See #25907 and #26101 for background: apparently gcov now has a feature
 where it can tell us that a line was reached, but not every basic block
 within the line was reached.

 Right now, our unit tests have two cases where sometimes a line is
 completely covered, and sometime the line is only partially covered:

 {{{
 --- a/workqueue.c.gcov.tmp
 +++ /workqueue.c.gcov.tmp
 @@ -198,7 +198,7 @@
          1:  tor_mutex_acquire(&ent->on_pool->lock);
          1:  workqueue_priority_t prio = ent->priority;
          1:  if (ent->pending) {
 -        1*:    TOR_TAILQ_REMOVE(&ent->on_pool->work[prio], ent,
 next_work);
 +        1:    TOR_TAILQ_REMOVE(&ent->on_pool->work[prio], ent,
 next_work);
          1:    cancelled = 1;
          1:    result = ent->arg;
          -:  }
 }}}

 {{{
 --- a/compat_pthreads.c.gcov.tmp
 +++ /compat_pthreads.c.gcov.tmp
 @@ -271,7 +271,7 @@
          -:      }
          1:      tvnow.tv_sec = ts.tv_sec;
          1:      tvnow.tv_usec = (int)(ts.tv_nsec / 1000);
 -        1*:      timeradd(tv, &tvnow, &tvsum);
 +        1:      timeradd(tv, &tvnow, &tvsum);
          -:#else /* !(defined(HAVE_CLOCK_GETTIME) &&
 defined(USE_COND_CLOCK)) */
          -:      if (gettimeofday(&tvnow, NULL) < 0)
          -:        return -1;
 }}}

 Unless coveralls cares about these, I think solving the determinism here
 is not super-important, though it might be fun from a completionist
 perspective.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/26105>
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