add cuda::Stream constructor with cuda flags

modules/core/test/test_cuda.cpp

@@ -0,0 +1,21 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+
+#if defined(HAVE_CUDA)
+
+#include "test_precomp.hpp"
+#include <cuda_runtime.h>
+#include "opencv2/core/cuda.hpp"
+
+namespace opencv_test { namespace {
+
+TEST(CUDA_Stream, construct_cudaFlags)
+{
+    cv::cuda::Stream stream(cudaStreamNonBlocking);
+    EXPECT_NE(stream.cudaPtr(), nullptr);
+}
+
+}} // namespace
+
+#endif