Fixed uniniitialized mats in tests, added operator<< for compare_f

modules/gapi/perf/common/gapi_core_perf_tests_inl.hpp

@@ -1678,6 +1678,7 @@ PERF_TEST_P_(LUTPerfTest, TestPerformance)
     initMatrixRandU(type_mat, sz_in, type_out);
     cv::Size sz_lut = cv::Size(1, 256);
     cv::Mat in_lut(sz_lut, type_lut);
+    cv::randu(in_lut, cv::Scalar::all(0), cv::Scalar::all(255));
 
     // OpenCV code ///////////////////////////////////////////////////////////
     cv::LUT(in_mat1, in_lut, out_mat_ocv);

modules/gapi/test/common/gapi_core_tests_inl.hpp

@@ -1373,7 +1373,8 @@ TEST_P(LUTTest, AccuracyTest)
 
     initMatrixRandU(type_mat, sz_in, type_out);
     cv::Size sz_lut = cv::Size(1, 256);
-    cv::Mat in_lut (sz_lut, type_lut);
+    cv::Mat in_lut(sz_lut, type_lut);
+    cv::randu(in_lut, cv::Scalar::all(0), cv::Scalar::all(255));
 
     // G-API code //////////////////////////////////////////////////////////////
     cv::GMat in;

modules/gapi/test/common/gapi_tests_common.hpp

@@ -377,6 +377,12 @@ public:
 private:
     double _tol;
 };
+} // namespace opencv_test
 
-
+namespace
+{
+    inline std::ostream& operator<<(std::ostream& os, const opencv_test::compare_f&)
+    {
+        return os << "compare_f";
+    }
 }

modules/gapi/test/gapi_scalar_tests.cpp

@@ -16,6 +16,7 @@ TEST(GAPI_Scalar, Argument)
 {
     cv::Size sz(2, 2);
     cv::Mat in_mat(sz, CV_8U);
+    cv::randn(in_mat, cv::Scalar::all(127), cv::Scalar::all(40.f));
 
     cv::GComputationT<cv::GMat (cv::GMat, cv::GScalar)> mulS([](cv::GMat in, cv::GScalar c)
     {

modules/gapi/test/internal/gapi_int_recompilation_test.cpp

@@ -193,6 +193,7 @@ TEST(GComputationCompile, ReshapeRois)
     cv::GComputation cc(in, cv::gapi::resize(blurred, szOut));
 
     cv::Mat first_in_mat(8, 8, CV_8UC3);
+    cv::randn(first_in_mat, cv::Scalar::all(127), cv::Scalar::all(40.f));
     cv::Mat first_out_mat;
     auto fluidKernels = cv::gapi::combine(gapi::imgproc::fluid::kernels(),
                                           gapi::core::fluid::kernels(),
@@ -206,6 +207,7 @@ TEST(GComputationCompile, ReshapeRois)
         int width  = 4 + 2*i;
         int height = width;
         cv::Mat in_mat(width, height, CV_8UC3);
+        cv::randn(in_mat, cv::Scalar::all(127), cv::Scalar::all(40.f));
         cv::Mat out_mat = cv::Mat::zeros(szOut, CV_8UC3);
 
         int x = 0;