Add scheduler channel states unit test

src/test/test_scheduler.c

@@ -41,6 +41,8 @@ static circuitmux_t *mock_cgp_tgt_1 = NULL;
 static const circuitmux_policy_t *mock_cgp_val_1 = NULL;
 static circuitmux_t *mock_cgp_tgt_2 = NULL;
 static const circuitmux_policy_t *mock_cgp_val_2 = NULL;
+static int scheduler_compare_channels_mock_ctr = 0;
+static int scheduler_run_mock_ctr = 0;
 
 /* Setup for mock event stuff */
 static void mock_event_free_all(void);
@@ -51,9 +53,13 @@ static int circuitmux_compare_muxes_mock(circuitmux_t *cmux_1,
                                          circuitmux_t *cmux_2);
 static const circuitmux_policy_t * circuitmux_get_policy_mock(
     circuitmux_t *cmux);
+static int scheduler_compare_channels_mock(const void *c1_v,
+                                           const void *c2_v);
+static void scheduler_run_noop_mock(void);
 static struct event_base * tor_libevent_get_base_mock(void);
 
 /* Scheduler test cases */
+static void test_scheduler_channel_states(void *arg);
 static void test_scheduler_compare_channels(void *arg);
 static void test_scheduler_initfree(void *arg);
 static void test_scheduler_queue_heuristic(void *arg);
@@ -130,8 +136,7 @@ circuitmux_compare_muxes_mock(circuitmux_t *cmux_1,
     if (cmux_1 == mock_ccm_tgt_1 && cmux_2 == mock_ccm_tgt_2) result = -1;
     else if (cmux_1 == mock_ccm_tgt_2 && cmux_2 == mock_ccm_tgt_1) {
       result = 1;
-    }
-    else {
+    } else {
       if (cmux_1 == mock_ccm_tgt_1 || cmux_1 == mock_ccm_tgt_1) result = -1;
       else if (cmux_2 == mock_ccm_tgt_1 || cmux_2 == mock_ccm_tgt_2) {
         result = 1;
@@ -162,6 +167,28 @@ circuitmux_get_policy_mock(circuitmux_t *cmux)
   return result;
 }
 
+static int
+scheduler_compare_channels_mock(const void *c1_v,
+                                const void *c2_v)
+{
+  uintptr_t p1, p2;
+
+  p1 = (uintptr_t)(c1_v);
+  p2 = (uintptr_t)(c2_v);
+
+  ++scheduler_compare_channels_mock_ctr;
+
+  if (p1 == p2) return 0;
+  else if (p1 < p2) return 1;
+  else return -1;
+}
+
+static void
+scheduler_run_noop_mock(void)
+{
+  ++scheduler_run_mock_ctr;
+}
+
 static struct event_base *
 tor_libevent_get_base_mock(void)
 {
@@ -170,6 +197,125 @@ tor_libevent_get_base_mock(void)
 
 /* Test cases */
 
+static void
+test_scheduler_channel_states(void *arg)
+{
+  channel_t *ch1 = NULL, *ch2 = NULL;
+  int old_count;
+
+  (void)arg;
+
+  /* Set up libevent and scheduler */
+
+  mock_event_init();
+  MOCK(tor_libevent_get_base, tor_libevent_get_base_mock);
+  scheduler_init();
+  /*
+   * Install the compare channels mock so we can test
+   * scheduler_touch_channel().
+   */
+  MOCK(scheduler_compare_channels, scheduler_compare_channels_mock);
+  /*
+   * Disable scheduler_run so we can just check the state transitions
+   * without having to make everything it might call work too.
+   */
+  MOCK(scheduler_run, scheduler_run_noop_mock);
+
+  test_eq(smartlist_len(channels_pending), 0);
+
+  /* Set up a fake channel */
+  ch1 = new_fake_channel();
+  test_assert(ch1);
+
+  /* Start it off in OPENING */
+  ch1->state = CHANNEL_STATE_OPENING;
+  /* We'll need a cmux */
+  ch1->cmux = circuitmux_alloc();
+  /* Try to register it */
+  channel_register(ch1);
+  test_assert(ch1->registered);
+
+  /* It should start off in SCHED_CHAN_IDLE */
+  test_eq(ch1->scheduler_state,  SCHED_CHAN_IDLE);
+
+  /* Now get another one */
+  ch2 = new_fake_channel();
+  test_assert(ch2);
+  ch2->state = CHANNEL_STATE_OPENING;
+  ch2->cmux = circuitmux_alloc();
+  channel_register(ch2);
+  test_assert(ch2->registered);
+
+  /* Send it to SCHED_CHAN_WAITING_TO_WRITE */
+  scheduler_channel_has_waiting_cells(ch1);
+  test_eq(ch1->scheduler_state, SCHED_CHAN_WAITING_TO_WRITE);
+
+  /* This should send it to SCHED_CHAN_PENDING */
+  scheduler_channel_wants_writes(ch1);
+  test_eq(ch1->scheduler_state, SCHED_CHAN_PENDING);
+  test_eq(smartlist_len(channels_pending), 1);
+
+  /* Now send ch2 to SCHED_CHAN_WAITING_FOR_CELLS */
+  scheduler_channel_wants_writes(ch2);
+  test_eq(ch2->scheduler_state, SCHED_CHAN_WAITING_FOR_CELLS);
+
+  /* Drop ch2 back to idle */
+  scheduler_channel_doesnt_want_writes(ch2);
+  test_eq(ch2->scheduler_state, SCHED_CHAN_IDLE);
+
+  /* ...and back to SCHED_CHAN_WAITING_FOR_CELLS */
+  scheduler_channel_wants_writes(ch2);
+  test_eq(ch2->scheduler_state, SCHED_CHAN_WAITING_FOR_CELLS);
+
+  /* ...and this should kick ch2 into SCHED_CHAN_PENDING */
+  scheduler_channel_has_waiting_cells(ch2);
+  test_eq(ch2->scheduler_state, SCHED_CHAN_PENDING);
+  test_eq(smartlist_len(channels_pending), 2);
+
+  /* This should send ch2 to SCHED_CHAN_WAITING_TO_WRITE */
+  scheduler_channel_doesnt_want_writes(ch2);
+  test_eq(ch2->scheduler_state, SCHED_CHAN_WAITING_TO_WRITE);
+  test_eq(smartlist_len(channels_pending), 1);
+
+  /* ...and back to SCHED_CHAN_PENDING */
+  scheduler_channel_wants_writes(ch2);
+  test_eq(ch2->scheduler_state, SCHED_CHAN_PENDING);
+  test_eq(smartlist_len(channels_pending), 2);
+
+  /* Now we exercise scheduler_touch_channel */
+  old_count = scheduler_compare_channels_mock_ctr;
+  scheduler_touch_channel(ch1);
+  test_assert(scheduler_compare_channels_mock_ctr > old_count);
+
+  /* Close */
+  channel_mark_for_close(ch1);
+  test_eq(ch1->state, CHANNEL_STATE_CLOSING);
+  channel_mark_for_close(ch2);
+  test_eq(ch2->state, CHANNEL_STATE_CLOSING);
+  channel_closed(ch1);
+  test_eq(ch1->state, CHANNEL_STATE_CLOSED);
+  ch1 = NULL;
+  channel_closed(ch2);
+  test_eq(ch2->state, CHANNEL_STATE_CLOSED);
+  ch2 = NULL;
+
+  /* Shut things down */
+
+  channel_free_all();
+  scheduler_free_all();
+  mock_event_free_all();
+
+ done:
+  tor_free(ch1);
+  tor_free(ch2);
+
+  UNMOCK(scheduler_compare_channels);
+  UNMOCK(scheduler_run);
+  UNMOCK(tor_libevent_get_base);
+
+  return;
+}
+
 static void
 test_scheduler_compare_channels(void *arg)
 {
@@ -208,7 +354,7 @@ test_scheduler_compare_channels(void *arg)
   /* Equal-channel case */
   result = scheduler_compare_channels(&c1, &c1);
   test_eq(result, 0);
-  
+
   /* Distinct channels, distinct policies */
   result = scheduler_compare_channels(&c1, &c2);
   test_eq(result, -1);
@@ -303,6 +449,7 @@ test_scheduler_queue_heuristic(void *arg)
 }
 
 struct testcase_t scheduler_tests[] = {
+  { "channel_states", test_scheduler_channel_states, TT_FORK, NULL, NULL },
   { "compare_channels", test_scheduler_compare_channels,
     TT_FORK, NULL, NULL },
   { "initfree", test_scheduler_initfree, TT_FORK, NULL, NULL },