Fix test prob distr parameters that caused warnings.

They were causing the following warnings in circuitpadding/circuitpadding_sample_distribution:

     src/lib/math/prob_distr.c:1311:17: runtime error: division by zero
     SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior src/lib/math/prob_distr.c:1311:17 in
     src/lib/math/prob_distr.c:1219:49: runtime error: division by zero
     SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior src/lib/math/prob_distr.c:1219:49 in

because the distributions were called with erroneous parameters (e.g. geometric
distribution with p=0).

We now defined these test probability distributions with more realistic
parameters.

As far as the circuitpadding_sample_distribution() test is concerned, it
doesn't matter if the distributions return values outside of [0,10] since we
already restrict the values into that interval using min=0 and max=10 (and RTT
estimate is disabled).

1 files changed, 16 insertions, 14 deletions

diff --git a/src/test/test_circuitpadding.c b/src/test/test_circuitpadding.c
index 3570b179bd..d349a4d3c3 100644
--- a/src/test/test_circuitpadding.c
+++ b/src/test/test_circuitpadding.c
@@ -2096,6 +2096,7 @@ helper_circpad_circ_distribution_machine_setup(int min, int max)
   circpad_state_t *zero_st = &circ_client_machine.states[0];
   zero_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 1;
   zero_st->iat_dist.type = CIRCPAD_DIST_UNIFORM;
+  /* param2 is upper bound, param1 is lower */
   zero_st->iat_dist.param1 = min;
   zero_st->iat_dist.param2 = max;
   zero_st->dist_added_shift_usec = min;
@@ -2104,48 +2105,50 @@ helper_circpad_circ_distribution_machine_setup(int min, int max)
   circpad_state_t *first_st = &circ_client_machine.states[1];
   first_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 2;
   first_st->iat_dist.type = CIRCPAD_DIST_LOGISTIC;
-  first_st->iat_dist.param1 = min;
-  first_st->iat_dist.param2 = max;
+  /* param1 is Mu, param2 is sigma. */
+  first_st->iat_dist.param1 = 9;
+  first_st->iat_dist.param2 = 3;
   first_st->dist_added_shift_usec = min;
   first_st->dist_max_sample_usec = max;
 
   circpad_state_t *second_st = &circ_client_machine.states[2];
   second_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 3;
   second_st->iat_dist.type = CIRCPAD_DIST_LOG_LOGISTIC;
-  second_st->iat_dist.param1 = min;
-  second_st->iat_dist.param2 = max;
+  /* param1 is Alpha, param2 is 1.0/Beta */
+  second_st->iat_dist.param1 = 1;
+  second_st->iat_dist.param2 = 0.5;
   second_st->dist_added_shift_usec = min;
   second_st->dist_max_sample_usec = max;
 
   circpad_state_t *third_st = &circ_client_machine.states[3];
   third_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 4;
   third_st->iat_dist.type = CIRCPAD_DIST_GEOMETRIC;
-  third_st->iat_dist.param1 = min;
-  third_st->iat_dist.param2 = max;
+  /* param1 is 'p' (success probability) */
+  third_st->iat_dist.param1 = 0.2;
   third_st->dist_added_shift_usec = min;
   third_st->dist_max_sample_usec = max;
 
   circpad_state_t *fourth_st = &circ_client_machine.states[4];
   fourth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 5;
   fourth_st->iat_dist.type = CIRCPAD_DIST_WEIBULL;
-  fourth_st->iat_dist.param1 = min;
-  fourth_st->iat_dist.param2 = max;
+  /* param1 is k, param2 is Lambda */
+  fourth_st->iat_dist.param1 = 1.5;
+  fourth_st->iat_dist.param2 = 1;
   fourth_st->dist_added_shift_usec = min;
   fourth_st->dist_max_sample_usec = max;
 
   circpad_state_t *fifth_st = &circ_client_machine.states[5];
   fifth_st->next_state[CIRCPAD_EVENT_NONPADDING_RECV] = 6;
   fifth_st->iat_dist.type = CIRCPAD_DIST_PARETO;
-  fifth_st->iat_dist.param1 = min;
-  fifth_st->iat_dist.param2 = max;
+  /* param1 is sigma, param2 is xi */
+  fifth_st->iat_dist.param1 = 1;
+  fifth_st->iat_dist.param2 = 5;
   fifth_st->dist_added_shift_usec = min;
   fifth_st->dist_max_sample_usec = max;
 }
 
 /** Simple test that the padding delays sampled from a uniform distribution
  *  actually faill within the uniform distribution range. */
-/* TODO: Upgrade this test so that each state tests a different prob
- * distribution */
 static void
 test_circuitpadding_sample_distribution(void *arg)
 {
@@ -2159,8 +2162,7 @@ test_circuitpadding_sample_distribution(void *arg)
   MOCK(circpad_machine_schedule_padding,
        circpad_machine_schedule_padding_mock);
 
-  /* Initialize a machine with multiple probability distributions that should
-   * return values between 0 and 5 */
+  /* Initialize a machine with multiple probability distributions */
   circpad_machines_init();
   helper_circpad_circ_distribution_machine_setup(0, 10);