[tor-commits] [tor/master] Hold monotonic time constant during channel/outbound_cell test

[nickm at torproject.org]

commit 24299d385d38a254eabde531a8f4f7830ecb088d
Author: Nick Mathewson <nickm at torproject.org>
Date:   Tue May 1 18:44:11 2018 -0400

    Hold monotonic time constant during channel/outbound_cell test
    
    This change should make it impossible for the monotonic time to roll
    over from one EWMA tick to the next during this test, and make it so
    that this test never invokes scale_active_circuits() (which it
    doesn't test).
    
    (Earlier changes during the 0.3.4 series should make this call even
    rarer than it was before, since we fixed #25927 and removed
    cached_gettimeofday.  Because this test didn't update
    cached_gettimeofday, the chance of rolling over a 10-second interval
    was much higher.)
    
    Closes ticket 25994; bugfix on 0.3.3.1-alpha when this test was
    introduced.
---
 changes/ticket25994     | 5 +++++
 src/test/test_channel.c | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/changes/ticket25994 b/changes/ticket25994
new file mode 100644
index 000000000..135417401
--- /dev/null
+++ b/changes/ticket25994
@@ -0,0 +1,5 @@
+  o Minor bugfixes (tests):
+    - Change the behavior of the "channel/outbound" test so that it never
+      causes a 10-second rollover for the EWMA circuitmux code. Previously,
+      this behavior would happen randomly, and result in fluctuating test
+      coverage. Fixes bug 25994; bugfix on 0.3.3.1-alpha.
diff --git a/src/test/test_channel.c b/src/test/test_channel.c
index 7d5018ef5..b20063c85 100644
--- a/src/test/test_channel.c
+++ b/src/test/test_channel.c
@@ -544,6 +544,11 @@ test_channel_outbound_cell(void *arg)
 
   (void) arg;
 
+  /* Set the test time to be mocked, since this test assumes that no
+   * time will pass, ewma values will not need to be re-scaled, and so on */
+  monotime_enable_test_mocking();
+  monotime_set_mock_time_nsec(U64_LITERAL(1000000000) * 12345);
+
   cmux_ewma_set_options(NULL,NULL);
 
   /* The channel will be freed so we need to hijack this so the scheduler
@@ -660,6 +665,7 @@ test_channel_outbound_cell(void *arg)
   tor_free(p_cell);
   channel_free_all();
   UNMOCK(scheduler_release_channel);
+  monotime_disable_test_mocking();
 }
 
 /* Test inbound cell. The callstack is: