CDRIVER-4353 unskip /server_discovery_and_monitoring/monitoring/heartbeat/pooled/dns (#1440)

* unskip `/server_discovery_and_monitoring/monitoring/heartbeat/pooled/dns`

* use `.invalid` TLD in test

To reliably return DNS error

* remove unnecessary test skips

Test expects to fail DNS lookup. Does not require internet.

* remove unused `test_framework_skip_if_rhel8_zseries`

* reduce serverSelectionTimeoutMS to speed up test

* update comment and expected error

* measure duration after destroy client or pool

Destroying the client or pool results in sending `endSessions`. This may result in another heartbeat attempt.

Author: kevinAlbs

.evergreen/etc/skip-tests.txt

@@ -37,6 +37,5 @@
 /transactions/legacy/mongos-recovery-token/"commitTransaction retry fails on new mongos" # fails with server selection timeout (CDRIVER-4268)
 /transactions/legacy/pin-mongos/"unpin after transient error within a transaction and commit" # (CDRIVER-4351) server selection timeout (on ASAN Tests Ubuntu 18.04 build variant)
 /Samples # (CDRIVER-4352) strange "heartbeat failed" error
-/server_discovery_and_monitoring/monitoring/heartbeat/pooled/dns # (CDRIVER-4353) this initially seemed like a zSeries w/ RHEL8 issue, but it also appeared on arm64 w/ Ubuntu 18.04
 
 /client_side_encryption/bypass_spawning_mongocryptd/mongocryptdBypassSpawn  # Fails if crypt_shared is visible

src/libmongoc/tests/test-libmongoc.c

@@ -1998,31 +1998,6 @@ test_framework_skip_if_offline (void)
 }
 
 
-int
-test_framework_skip_if_rhel8_zseries (void)
-{
-   /* CDRIVER-3923: It appears that when running on RHEL8 on zSeries the
-    * /server_discovery_and_monitoring/monitoring/heartbeat/pooled/dns test
-    * fails.  The best guess is that calling getaddrinfo() on that platform
-    * blocks for 5 seconds, while the test expects a server selection error
-    * after 3000 ms, or 3 seconds.  Skip the test when executing on RHEL8 on
-    * zSeries. */
-#ifdef __s390x__
-   char *name;
-   char *version;
-   _mongoc_linux_distro_scanner_get_distro (&name, &version);
-   bool rhel = strcmp (name, "Red Hat Enterprise Linux") == 0;
-   bool vers8 = version[0] == '8';
-   int skip = (rhel && vers8) ? 0 : 1;
-   bson_free (name);
-   bson_free (version);
-   return skip;
-#else
-   return 1;
-#endif
-}
-
-
 int
 test_framework_skip_if_slow (void)
 {

src/libmongoc/tests/test-libmongoc.h

@@ -189,8 +189,6 @@ test_framework_skip_if_not_single (void);
 int
 test_framework_skip_if_offline (void);
 int
-test_framework_skip_if_rhel8_zseries (void);
-int
 test_framework_skip_if_slow (void);
 int
 test_framework_skip_if_slow_or_live (void);

src/libmongoc/tests/test-mongoc-sdam-monitoring.c

@@ -848,7 +848,7 @@ _test_heartbeat_fails_dns (bool pooled)
     * client for a client pool). */
    start = bson_get_monotonic_time ();
    uri = mongoc_uri_new (
-      "mongodb://doesntexist.foobar/?serverSelectionTimeoutMS=3000");
+      "mongodb://doesntexist.invalid/?serverSelectionTimeoutMS=100");
    if (pooled) {
       pool = test_framework_client_pool_new_from_uri (uri, NULL);
       pool_set_heartbeat_event_callbacks (pool, &context);
@@ -862,15 +862,13 @@ _test_heartbeat_fails_dns (bool pooled)
    r = mongoc_client_command_simple (
       client, "admin", tmp_bson ("{'foo': 1}"), NULL, NULL, &error);
 
-   /* This should result in either a DNS failure or connection failure depending
-    * on the network. We assert the domain/code but not the message string. */
+   /* Expect a server selection error. */
    ASSERT (!r);
    ASSERT_ERROR_CONTAINS (error,
                           MONGOC_ERROR_SERVER_SELECTION,
                           MONGOC_ERROR_SERVER_SELECTION_FAILURE,
-                          "");
+                          "No suitable servers found");
 
-   duration = bson_get_monotonic_time () - start;
 
    if (pooled) {
       mongoc_client_pool_push (pool, client);
@@ -879,6 +877,8 @@ _test_heartbeat_fails_dns (bool pooled)
       mongoc_client_destroy (client);
    }
 
+   duration = bson_get_monotonic_time () - start;
+
    durations = &context.heartbeat_failed_durations;
 
    ASSERT_CMPSIZE_T (durations->len, >, (size_t) 0);
@@ -893,18 +893,14 @@ _test_heartbeat_fails_dns (bool pooled)
 }
 
 static void
-test_heartbeat_fails_dns_single (void *ctx)
+test_heartbeat_fails_dns_single (void)
 {
-   BSON_UNUSED (ctx);
-
    _test_heartbeat_fails_dns (false);
 }
 
 static void
-test_heartbeat_fails_dns_pooled (void *ctx)
+test_heartbeat_fails_dns_pooled (void)
 {
-   BSON_UNUSED (ctx);
-
    _test_heartbeat_fails_dns (true);
 }
 
@@ -1054,21 +1050,14 @@ test_sdam_monitoring_install (TestSuite *suite)
       suite,
       "/server_discovery_and_monitoring/monitoring/heartbeat/pooled/failed",
       test_heartbeat_events_pooled_failed);
-   TestSuite_AddFull (
+   TestSuite_Add (
       suite,
       "/server_discovery_and_monitoring/monitoring/heartbeat/single/dns",
-      test_heartbeat_fails_dns_single,
-      NULL,
-      NULL,
-      test_framework_skip_if_offline);
-   TestSuite_AddFull (
+      test_heartbeat_fails_dns_single);
+   TestSuite_Add (
       suite,
       "/server_discovery_and_monitoring/monitoring/heartbeat/pooled/dns",
-      test_heartbeat_fails_dns_pooled,
-      NULL,
-      NULL,
-      test_framework_skip_if_offline,
-      test_framework_skip_if_rhel8_zseries);
+      test_heartbeat_fails_dns_pooled);
    TestSuite_AddMockServerTest (
       suite,
       "/server_discovery_and_monitoring/monitoring/no_duplicates",