message: core(test): add InputArray(MatExpr) fetch test
diff: @@ -1969,6 +1969,21 @@ TEST(Core_InputArray, support_CustomType)
  }
  }
  +
  +TEST(Core_InputArray, fetch_MatExpr)
  +{
  + Mat a(Size(10, 5), CV_32FC1, 5);
  + Mat b(Size(10, 5), CV_32FC1, 2);
  + MatExpr expr = a * b.t(); // gemm expression
  + Mat dst;
  + cv::add(expr, Scalar(1), dst); // invoke gemm() here
  + void* expr_data = expr.a.data;
  + Mat result = expr; // should not call gemm() here again
  + EXPECT_EQ(expr_data, result.data); // expr data is reused
  + EXPECT_EQ(dst.size(), result.size());
  +}
  +
  +
  TEST(Core_Vectors, issue_13078)
  {
  float floats_[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
  