disabled utility code in gpu tests when WITH_CUDA=false

modules/gpu/test/main_test_nvidia.h

 #ifndef __main_test_nvidia_h__
 #define __main_test_nvidia_h__
 
-#include <string>
-
 enum OutputLevel
 {
     OutputLevelNone,

modules/gpu/test/test_nvidia.cpp

@@ -41,13 +41,13 @@
 
 #include "test_precomp.hpp"
 
-OutputLevel nvidiaTestOutputLevel = OutputLevelCompact;
-
 #ifdef HAVE_CUDA
 
 using namespace cvtest;
 using namespace testing;
 
+OutputLevel nvidiaTestOutputLevel = OutputLevelCompact;
+
 struct NVidiaTest : TestWithParam<cv::gpu::DeviceInfo>
 {
     cv::gpu::DeviceInfo devInfo;

modules/gpu/test/test_precomp.hpp

@@ -61,24 +61,24 @@
 
 #include "cvconfig.h"
 
-#include "opencv2/core/core.hpp"
-#include "opencv2/highgui/highgui.hpp"
-#include "opencv2/calib3d/calib3d.hpp"
-#include "opencv2/imgproc/imgproc.hpp"
-#include "opencv2/video/video.hpp"
-#include "opencv2/ts/ts.hpp"
-#include "opencv2/ts/ts_perf.hpp"
-#include "opencv2/gpu/gpu.hpp"
-#include "opencv2/nonfree/nonfree.hpp"
-#include "opencv2/legacy/legacy.hpp"
-
-#include "utility.hpp"
-#include "interpolation.hpp"
-#include "main_test_nvidia.h"
-
 #ifdef HAVE_CUDA
     #include <cuda.h>
     #include <cuda_runtime.h>
+
+    #include "opencv2/core/core.hpp"
+    #include "opencv2/highgui/highgui.hpp"
+    #include "opencv2/calib3d/calib3d.hpp"
+    #include "opencv2/imgproc/imgproc.hpp"
+    #include "opencv2/video/video.hpp"
+    #include "opencv2/ts/ts.hpp"
+    #include "opencv2/ts/ts_perf.hpp"
+    #include "opencv2/gpu/gpu.hpp"
+    #include "opencv2/nonfree/nonfree.hpp"
+    #include "opencv2/legacy/legacy.hpp"
+
+    #include "utility.hpp"
+    #include "interpolation.hpp"
+    #include "main_test_nvidia.h"
 #endif
 
 #endif

modules/gpu/test/utility.cpp

@@ -41,6 +41,8 @@
 
 #include "test_precomp.hpp"
 
+#ifdef HAVE_CUDA
+
 using namespace std;
 using namespace cv;
 using namespace cv::gpu;
@@ -418,3 +420,5 @@ void showDiff(InputArray gold_, InputArray actual_, double eps)
 
     waitKey();
 }
+
+#endif // HAVE_CUDA

modules/gpu/test/utility.hpp

@@ -42,14 +42,6 @@
 #ifndef __OPENCV_TEST_UTILITY_HPP__
 #define __OPENCV_TEST_UTILITY_HPP__
 
-#include <vector>
-#include <string>
-#include "opencv2/core/core.hpp"
-#include "opencv2/highgui/highgui.hpp"
-#include "opencv2/gpu/gpu.hpp"
-#include "opencv2/ts/ts.hpp"
-#include "opencv2/ts/ts_perf.hpp"
-
 //////////////////////////////////////////////////////////////////////
 // random generators