COMPMID-670 - Extend Sobel tests

Change-Id: Ibf15544e8624977815ee355071a038c07e1f01c2
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/94874
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
diff --git a/tests/validation/CPP/HarrisCornerDetector.cpp b/tests/validation/CPP/HarrisCornerDetector.cpp
index 3babfee..6cfcd8e 100644
--- a/tests/validation/CPP/HarrisCornerDetector.cpp
+++ b/tests/validation/CPP/HarrisCornerDetector.cpp
@@ -45,7 +45,7 @@
     SimpleTensor<T> grad_y;
     float           norm_factor = 0.f;
 
-    std::tie(grad_x, grad_y) = sobel<T>(src, gradient_size, border_mode, constant_border_value);
+    std::tie(grad_x, grad_y) = sobel<T>(src, gradient_size, border_mode, constant_border_value, GradientDimension::GRAD_XY);
 
     switch(gradient_size)
     {