BarrierTest: Keep queue flushing

This will keep the queue flushing its contents so FIFO behaviour is
emulated.

coalib/tests/processes/BarrierTest.py

@@ -31,15 +31,14 @@ def test_barrier(self):
                                              args=(queue, uut))]
         for proc in processes:
             proc.start()
+
+        # Order will probably be wrong (1 2 1 2) if barrier doesn't work
+        for expected in [1, 1, 2, 2]:
+            self.assertEqual(queue.get(), expected)
+
         for proc in processes:
             proc.join()
 
-        # Order will be wrong (1 2 1 2) if barrier doesn't work
-        self.assertEqual(queue.get(), 1)
-        self.assertEqual(queue.get(), 1)
-        self.assertEqual(queue.get(), 2)
-        self.assertEqual(queue.get(), 2)
-
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)