dm: video: test: Add tests for the video uclass

Add tests that check that the video console is working correcty. Also check
that text output produces the expected result. Test coverage includes
character output, wrapping and scrolling.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>

include/dm/test.h

@@ -155,6 +155,14 @@ enum {
 /* Declare a new driver model test */
 #define DM_TEST(_name, _flags)	UNIT_TEST(_name, _flags, dm_test)
 
+/* This platform data is needed in tests, so declare it here */
+struct sandbox_sdl_plat {
+	int xres;
+	int yres;
+	int bpix;
+	int rot;
+};
+
 /* Declare ping methods for the drivers */
 int test_ping(struct udevice *dev, int pingval, int *pingret);
 int testfdt_ping(struct udevice *dev, int pingval, int *pingret);