A working solution

integral_image_tests.cpp

@@ -0,0 +1,49 @@
+#define CATCH_CONFIG_MAIN
+#include <thirdparty/catch.hpp>
+
+#include "integral_image.h"
+
+
+namespace {
+
+bool are_equal(const integral_image::Mat &lhv, const integral_image::Mat &rhv)
+{
+    auto diff = (lhv != rhv);
+    return cv::countNonZero(diff) == 0;
+}
+
+}
+
+
+TEST_CASE("Integral image of an empty Mat is an empty Mat")
+{
+    using namespace integral_image;
+
+    Mat  input;
+    auto output = integral_image_openmp(input);
+
+    REQUIRE(output.data == NULL);
+}
+
+TEST_CASE("Integral image of a zero-valued Mat is the same sized zero-valued Mat")
+{
+    using namespace integral_image;
+
+    Mat input   = Mat::zeros(20, 18);
+    auto output = integral_image_openmp(input);
+    REQUIRE(are_equal(input, output));
+}
+
+TEST_CASE("")
+{
+    using namespace integral_image;
+
+    double input_values[] = {0, 1, 2, 3, 4, 5};
+    double expected_output_values[] = {0., 1., 2., 6., 6., 15.};
+
+    Mat input(3, 2, input_values);
+    Mat expected_output(3, 2, expected_output_values);
+
+    auto output = integral_image_openmp(input);
+    REQUIRE(are_equal(expected_output, output));
+}