[lldb] Script determinism of TestSwiftActorUnprioritisedJobs

lldb/test/API/lang/swift/async/actors/unprioritised_jobs/TestSwiftActorUnprioritisedJobs.py

@@ -1,30 +1,54 @@
+import time
+from contextlib import contextmanager
 import lldb
 from lldbsuite.test.decorators import *
 from lldbsuite.test.lldbtest import *
 from lldbsuite.test import lldbutil
 
 
+@contextmanager
+def _managed_async(dbg):
+    async_state = dbg.GetAsync()
+    try:
+        yield
+    finally:
+        dbg.SetAsync(async_state)
+
+
 class TestCase(TestBase):
 
     @swiftTest
-    @skipUnlessFoundation
-    @skipIfWindows  # temporarily skip test until fails can be investigated
-    @skipIfLinux    # temporarily skip test until fails can be investigated
-    @skipIfDarwin   # temporarily skip test until fails can be investigated
     def test_actor_unprioritised_jobs(self):
         """Verify that an actor exposes its unprioritised jobs (queue)."""
         self.build()
-        _, _, thread, _ = lldbutil.run_to_source_breakpoint(
+        _, process, thread, _ = lldbutil.run_to_source_breakpoint(
             self, "break here", lldb.SBFileSpec("main.swift")
         )
         frame = thread.GetSelectedFrame()
+
+        with _managed_async(self.dbg):
+            # Suspend the current thread.
+            thread.Suspend()
+            # Continue - other threads only.
+            self.dbg.SetAsync(True)
+            process.Continue()
+            # Wait - allowing other threads to run.
+            time.sleep(5)
+            # Stop the threads.
+            self.dbg.SetAsync(False)
+            self.dbg.HandleCommand("process interrupt")
+            # Note: After a single interrupt, lldb reports the process as
+            # running, but two interrupt calls results in a stopped process.
+            # Also, using `process.Stop()` instead of `"process interrupt"`
+            # did not work.
+            self.dbg.HandleCommand("process interrupt")
+
         defaultActor = frame.var("a.$defaultActor")
-        self.assertEqual(defaultActor.summary, "running")
         unprioritised_jobs = defaultActor.GetChildMemberWithName("unprioritised_jobs")
         # There are 4 child tasks (async let), the first one occupies the actor
         # with a sleep, the next 3 go on to the queue.
-        # TODO: rdar://148377173
-        # self.assertEqual(unprioritised_jobs.num_children, 3)
+        self.assertEqual(unprioritised_jobs.num_children, 3)
+        self.assertEqual(defaultActor.summary, "running")
         for job in unprioritised_jobs:
             self.assertRegex(job.name, r"^\d+")
             self.assertRegex(job.summary, r"^id:\d+ flags:\S+")

lldb/test/API/lang/swift/async/actors/unprioritised_jobs/main.swift

@@ -1,10 +1,8 @@
-import Foundation
-
 actor Actor {
     var data: Int = 15
 
     func occupy() async {
-        Thread.sleep(forTimeInterval: 100)
+        _ = readLine()
     }
 
     func work() async -> Int {