test(profiling): enhance gevent thread hub/task detection (#2990)

This test regularly fails because the first events from the stack collector are
from the gevent thread booting up, while we expect to get frames from the
thread running.

This changes the test to ignore events where we see the thread boot time, and
only look for when the thread actually runs. If we find it once, we know we're
good.

Author: Julien Danjou

tests/profiling/collector/test_stack.py

@@ -605,9 +605,9 @@ def test_collect_gevent_thread_hub():
 
     # Start some greenthreads: they do nothing we just keep switching between them.
     def _nothing():
-        for _ in range(10000):
+        for _ in range(100):
             # Do nothing and just switch to another greenlet
-            time.sleep(0)
+            time.sleep(0.01)
 
     threads = []
     with s:
@@ -619,24 +619,21 @@ def _nothing():
             t.join()
 
     main_thread_found = False
-    for event in r.events[stack.StackSampleEvent]:
+    sleep_task_found = False
+    events = r.events[stack.StackSampleEvent]
+    for event in events:
         if event.task_id == compat.main_thread.ident:
             if event.task_name is None:
                 pytest.fail("Task with no name detected, is it the Hub?")
             else:
                 main_thread_found = True
-        elif event.task_id in {t.ident for t in threads}:
+        elif event.task_id in {t.ident for t in threads} and event.frames[0][2] in (
+            "_nothing",
+            "sleep",
+        ):
             # Make sure we capture the sleep call and not a gevent hub frame
-            assert event.frames[0][2] in (
-                "_nothing",
-                "sleep",
-                "get_ident",
-                "__bootstrap_inner",
-                "_bootstrap_inner",
-                "switch",
-                "run",
-                "notify",
-            )
+            sleep_task_found = True
 
     # Make sure we did at least one check
-    assert main_thread_found
+    assert main_thread_found, events
+    assert sleep_task_found, events