[UTest] Fix #213: Increase delays in async test.

Increase delays in an asynchronous / multi-threaded test to reduce the
chance of odd scheduling.

The test randomly and infrequently failed before, as the scheduling
could be different than expected.  Our delays were simply not long
enough.  `fork()` can take a considerable amount of time...

This test **did not fail** because of data races or other
synchronization issues.

Author: ImmanuelHaffner

unittest/util/reader_writer_lock_test.cpp

@@ -41,37 +41,37 @@ TEST_CASE("reader_writer_mutex/reader_writer_lock/3_readers_2_writers", "[core][
         lock.lock_write();
         M_insist(lock.owns_write_lock());
         shared_value += delta;
-        std::this_thread::sleep_for(5ms);
+        std::this_thread::sleep_for(50ms);
     };
 
     auto read = [&mutex, &shared_value](int &dest) {
         reader_writer_lock lock{mutex};
         lock.lock_read();
         M_insist(lock.owns_read_lock());
         dest = shared_value;
-        std::this_thread::sleep_for(5ms);
+        std::this_thread::sleep_for(50ms);
     };
 
-    /* Spawn first reader, taking 5ms. */
+    /* Spawn first reader, taking 50ms. */
     std::thread tr1{read, std::ref(r1)};
-    std::this_thread::sleep_for(1ms);
+    std::this_thread::sleep_for(10ms);
 
-    /* Spawn first writer, taking 5ms.  It is blocked by the first reader. */
+    /* Spawn first writer, taking 50ms.  It is blocked by the first reader. */
     std::thread tw1{write, 1};
-    std::this_thread::sleep_for(1ms);
+    std::this_thread::sleep_for(10ms);
 
     /* Spawn second reader.  The first reader should still be active while the first writer is still blocked.
      * Therefore, the newly spawned second reader should wait for the writer to finish. */
     std::thread tr2{read, std::ref(r2)};
-    std::this_thread::sleep_for(1ms);
+    std::this_thread::sleep_for(10ms);
 
     /* Spawn second writer. */
     std::thread tw2{write, 2};
-    std::this_thread::sleep_for(1ms);
+    std::this_thread::sleep_for(10ms);
 
     /* Spawn third reader. */
     std::thread tr3{read, std::ref(r3)};
-    std::this_thread::sleep_for(1ms);
+    std::this_thread::sleep_for(10ms);
 
     tr1.join();
     tr2.join();
@@ -93,36 +93,36 @@ TEST_CASE("reader_writer_mutex/read_lock_write_lock/3_readers_2_writers", "[core
         write_lock lock{mutex};
         M_insist(lock.owns_lock());
         shared_value += delta;
-        std::this_thread::sleep_for(5ms);
+        std::this_thread::sleep_for(50ms);
     };
 
     auto read = [&mutex, &shared_value](int &dest) {
         read_lock lock{mutex};
         M_insist(lock.owns_lock());
         dest = shared_value;
-        std::this_thread::sleep_for(5ms);
+        std::this_thread::sleep_for(50ms);
     };
 
-    /* Spawn first reader, taking 5ms. */
+    /* Spawn first reader, taking 50ms. */
     std::thread tr1{read, std::ref(r1)};
-    std::this_thread::sleep_for(1ms);
+    std::this_thread::sleep_for(10ms);
 
-    /* Spawn first writer, taking 5ms.  It is blocked by the first reader. */
+    /* Spawn first writer, taking 50ms.  It is blocked by the first reader. */
     std::thread tw1{write, 1};
-    std::this_thread::sleep_for(1ms);
+    std::this_thread::sleep_for(10ms);
 
     /* Spawn second reader.  The first reader should still be active while the first writer is still blocked.
      * Therefore, the newly spawned second reader should wait for the writer to finish. */
     std::thread tr2{read, std::ref(r2)};
-    std::this_thread::sleep_for(1ms);
+    std::this_thread::sleep_for(10ms);
 
     /* Spawn second writer. */
     std::thread tw2{write, 2};
-    std::this_thread::sleep_for(1ms);
+    std::this_thread::sleep_for(10ms);
 
     /* Spawn third reader. */
     std::thread tr3{read, std::ref(r3)};
-    std::this_thread::sleep_for(1ms);
+    std::this_thread::sleep_for(10ms);
 
     tr1.join();
     tr2.join();