Trick unittest to avoid work-around

Signed-off-by: Larsen, Steffen <[email protected]>

Author: steffenlarsen

sycl/unittests/Extensions/ExtOneapiBarrierOpt.cpp

@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include <detail/queue_impl.hpp>
 #include <gtest/gtest.h>
 #include <helpers/ScopedEnvVar.hpp>
 #include <helpers/UrMock.hpp>
@@ -39,6 +40,11 @@ class ExtOneapiBarrierOptTest : public ::testing::Test {
 TEST_F(ExtOneapiBarrierOptTest, EmptyEventTest) {
   sycl::queue q1{{sycl::property::queue::in_order()}};
 
+  // To avoid current optimizations for empty queues, we trick q1 into thinking
+  // that it isn't empty.
+  int dummyInt;
+  q1.prefetch(&dummyInt, sizeof(int));
+
   mock::getCallbacks().set_after_callback(
       "urEnqueueEventsWaitWithBarrierExt",
       &redefinedEnqueueEventsWaitWithBarrierExt);