From 086316057b5dfd8f16288d35b0aa655e0b59947c Mon Sep 17 00:00:00 2001
From: Timothy Flynn <trflynn89@pm.me>
Date: Tue, 23 May 2023 12:31:13 -0400
Subject: [PATCH] LibThreading: Improve resiliancy of timed threading tests

The threading tests currently wait for a very small amount of time for
the expected test condition to be reached, e.g. 20ms. This changes the
tests to *check* the condition every 20ms, but allow the test to run for
up to 2s until the condition is reached. This should hopefully resolve
the failures seen on CI.

This also renames one of the tests to match what it actually does. The
test itself was changed in commit 5b335e7, but the name was not updated
to reflect that change.
---
 Tests/LibThreading/TestThread.cpp | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/Tests/LibThreading/TestThread.cpp b/Tests/LibThreading/TestThread.cpp
index 1ffee96dc8e..c5a483c42b8 100644
--- a/Tests/LibThreading/TestThread.cpp
+++ b/Tests/LibThreading/TestThread.cpp
@@ -4,13 +4,30 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/Time.h>
 #include <LibTest/TestCase.h>
 #include <LibThreading/Thread.h>
 #include <unistd.h>
 
+using namespace AK::TimeLiterals;
+
+static void sleep_until_thread_exits(Threading::Thread const& thread)
+{
+    static constexpr auto delay = 20_ms;
+
+    for (auto i = 0; i < 100; ++i) {
+        if (thread.has_exited())
+            return;
+
+        usleep(delay.to_microseconds());
+    }
+
+    FAIL("Timed out waiting for thread to exit");
+}
+
 TEST_CASE(threads_can_detach)
 {
-    int should_be_42 = 0;
+    Atomic<int> should_be_42 = 0;
 
     auto thread = Threading::Thread::construct([&should_be_42]() {
         usleep(10 * 1000);
@@ -19,12 +36,12 @@ TEST_CASE(threads_can_detach)
     });
     thread->start();
     thread->detach();
-    usleep(20 * 1000);
 
+    sleep_until_thread_exits(*thread);
     EXPECT(should_be_42 == 42);
 }
 
-TEST_CASE(joining_detached_thread_errors)
+TEST_CASE(detached_threads_do_not_need_to_be_joined)
 {
     Atomic<bool> should_exit { false };
     auto thread = Threading::Thread::construct([&]() {
@@ -40,15 +57,16 @@ TEST_CASE(joining_detached_thread_errors)
 
     // FIXME: Dropping a running thread crashes because of the Function destructor. For now, force the detached thread to exit.
     should_exit.store(true);
-    usleep(20 * 1000);
+    sleep_until_thread_exits(*thread);
 }
 
 TEST_CASE(join_dead_thread)
 {
     auto thread = Threading::Thread::construct([&]() { return 0 /*nullptr*/; });
     thread->start();
+
     // The thread should have exited by then.
-    usleep(40 * 1000);
+    sleep_until_thread_exits(*thread);
 
     auto join_result = TRY_OR_FAIL(thread->join<int*>());
     EXPECT_EQ(join_result, static_cast<int*>(0));