Fix sanity checks for empty objects

modules/ts/src/ts_perf.cpp

@@ -392,6 +392,13 @@ void Regression::verify(cv::FileNode node, cv::InputArray array, double eps, ERR
             cv::Mat expected;
             valnode >> expected;
 
+            if(expected.empty())
+            {
+                ASSERT_TRUE(actual.empty())
+                    << "  expected empty " << node.name() << "[" <<  idx<< "]";
+            }
+            else
+            {
                 ASSERT_EQ(expected.size(), actual.size())
                         << "  " << node.name() << "[" <<  idx<< "] has unexpected size";
 
@@ -402,8 +409,12 @@ void Regression::verify(cv::FileNode node, cv::InputArray array, double eps, ERR
                 {
                     if (!cv::checkRange(diff, true, 0, 0, eps))
                     {
+                        if(expected.total() * expected.channels() < 12)
+                            std::cout << " Expected: " << std::endl << expected << std::endl << " Actual:" << std::endl << actual << std::endl;
+
                         double max;
                         cv::minMaxLoc(diff.reshape(1), 0, &max);
+
                         FAIL() << "  Absolute difference (=" << max << ") between argument \""
                                << node.name() << "[" <<  idx << "]\" and expected value is bugger than " << eps;
                     }
@@ -420,6 +431,7 @@ void Regression::verify(cv::FileNode node, cv::InputArray array, double eps, ERR
                 }
             }
         }
+    }
     else
     {
         if (valnode.isNone())
@@ -434,6 +446,13 @@ void Regression::verify(cv::FileNode node, cv::InputArray array, double eps, ERR
             valnode >> expected;
             cv::Mat actual = array.getMat();
 
+            if(expected.empty())
+            {
+                ASSERT_TRUE(actual.empty())
+                    << "  expected empty " << node.name();
+            }
+            else
+            {
                 ASSERT_EQ(expected.size(), actual.size())
                         << "  Argument \"" << node.name() << "\" has unexpected size";
 
@@ -444,9 +463,13 @@ void Regression::verify(cv::FileNode node, cv::InputArray array, double eps, ERR
                 {
                     if (!cv::checkRange(diff, true, 0, 0, eps))
                     {
+                        if(expected.total() * expected.channels() < 12)
+                            std::cout << " Expected: " << std::endl << expected << std::endl << " Actual:" << std::endl << actual << std::endl;
+
                         double max;
                         cv::minMaxLoc(diff.reshape(1), 0, &max);
-                    FAIL() << "  Difference (=" << max << ") between argument \"" << node.name()
+
+                        FAIL() << "  Difference (=" << max << ") between argument1 \"" << node.name()
                                << "\" and expected value is bugger than " << eps;
                     }
                 }
@@ -462,6 +485,7 @@ void Regression::verify(cv::FileNode node, cv::InputArray array, double eps, ERR
                 }
             }
         }
+    }
 }
 
 Regression& Regression::operator() (const std::string& name, cv::InputArray array, double eps, ERROR_TYPE err)