refactor: rework test to be more specific

modules/python/src2/cv2_convert.hpp

@@ -62,8 +62,9 @@ PyObject* pyopencv_from(const T& src) { return PyOpenCV_Converter<T>::from(src);
 template<typename _Tp, int m, int n>
 bool pyopencv_to(PyObject* o, cv::Matx<_Tp, m, n>& mx, const ArgInfo& info)
 {
-    if (!o || o == Py_None)
+    if (!o || o == Py_None) {
         return true;
+    }
 
     cv::Mat tmp;
     if (!pyopencv_to(o, tmp, info)) {

modules/python/test/test_misc.py

@@ -736,6 +736,13 @@ class CanUsePurePythonModuleFunction(NewOpenCVTests):
         res = cv.utils._native.testOverwriteNativeMethod(123)
         self.assertEqual(res, 123, msg="Failed to call native method implementation")
 
+    def test_default_matx_argument(self):
+        res = cv.utils.dumpVec2i()
+        self.assertEqual(res, "Vec2i(42, 24)",
+                         msg="Default argument is not properly handled")
+        res = cv.utils.dumpVec2i((12, 21))
+        self.assertEqual(res, "Vec2i(12, 21)")
+
 
 class SamplesFindFile(NewOpenCVTests):