Test that queues are flushed by clReleaseCommandQueue (#923)

... as required by the OpenCL specification.

Also introduce a utility function to manage polling for changes
via a user-supplied function. Several tests we introduced lately
could have used this.

Signed-off-by: Kévin Petit <kpet@free.fr>

test_conformance/api/test_queue.cpp

@@ -0,0 +1,61 @@
+//
+// Copyright (c) 2020 The Khronos Group Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+
+#include "testBase.h"
+#include "harness/typeWrappers.h"
+
+int test_queue_flush_on_release(cl_device_id deviceID, cl_context context,
+                                cl_command_queue defaultQueue, int num_elements)
+{
+    cl_int err;
+
+    // Create a command queue
+    cl_command_queue queue = clCreateCommandQueue(context, deviceID, 0, &err);
+    test_error(err, "Could not create command queue");
+
+    // Create a kernel
+    clProgramWrapper program;
+    clKernelWrapper kernel;
+    const char *source = "void kernel test(){}";
+    err = create_single_kernel_helper(context, &program, &kernel, 1, &source,
+                                      "test");
+    test_error(err, "Could not create kernel");
+
+    // Enqueue the kernel
+    size_t gws = 1;
+    clEventWrapper event;
+    err = clEnqueueNDRangeKernel(queue, kernel, 1, nullptr, &gws, nullptr, 0,
+                                 nullptr, &event);
+    test_error(err, "Could not enqueue kernel");
+
+    // Release the queue
+    err = clReleaseCommandQueue(queue);
+
+    // Wait for kernel to execute since the queue must flush on release
+    bool success = poll_until(2000, 50, [event]() {
+        cl_int status;
+        cl_int err = clGetEventInfo(event, CL_EVENT_COMMAND_EXECUTION_STATUS,
+                                    sizeof(cl_int), &status, nullptr);
+        if ((err != CL_SUCCESS) || (status != CL_COMPLETE))
+        {
+            return false;
+        }
+        return true;
+    });
+
+    return success ? TEST_PASS : TEST_FAIL;
+}