Semaphore.d unittest can fail

I have looked at the code more in depth and it is messy, I do not really understand what it does test, as it is not a queue (the number of consumer and products has to be equal for it to work correctly if I understood it correctly). Anyway as test it might be ok, if the probability of failure remains small.

The test assumes that all threads are started before the consumer sets allProduced=true but no thread is finished. As the semaphore.notify(); does not guarantee that the thread starts immediately this conditions might fail.

To make it more unlikely one should make the running time of the consumer long and of the producer a little bit longer for example like this:

--- tango/core/sync/Semaphore.d (revision 3432)
+++ tango/core/sync/Semaphore.d (working copy)
@@ -291,7 +291,8 @@
                     if( allProduced )
                         break;
                 }
-
+               for (int i=0;i<200;i++)
+                  Thread.yield();
                 synchronized( synConsumed )
                 {
                     ++numConsumed;
@@ -314,6 +315,8 @@
                 Thread.yield();
             }

+           for (int i=0;i<20;i++)
+               Thread.yield();
             synchronized( synProduced )
             {
                 allProduced = true;
@@ -325,21 +328,24 @@
                 Thread.yield();
             }

-            for( int i = numConsumers * 10; i > 0; --i )
+            for( int i = numConsumers * 1000; i > 0; --i )
             {
+                Thread.yield();
                 synchronized( synComplete )
                 {
                     if( numComplete == numConsumers )
                         break;
                 }
             }

             synchronized( synComplete )
             {
                 assert( numComplete == numConsumers );
             }
-            assert( numConsumed == numToProduce );
-
+            synchronized( synConsumed )
+           {
+                   assert( numConsumed == numToProduce );
+            }
             assert( !semaphore.tryWait() );
             semaphore.notify();
             assert( semaphore.tryWait() );

This changes (that also add an extra synchronization) make the failure much less likely, also under load (10 tests concurrently) I did not see any failures.

Verified to fail (most of the time after installing a composite manager) with both gdc and dmd on linux.

#1199 is marked as a duplicate and contains additional information.

(In [3813]) Made a few changes to imcrease the likelihood that the unit tests will succeed. This (hopefully) closes #1049

This still occasionally fails on line 345.

(In [3931]) Lengthened timeout for unittest. Hopefully this closes #1049