diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index fdac405..fff19da 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -2475,6 +2475,8 @@
 test_null_string()		String	null value for testing
 test_option_not_set({name})    none	reset flag indicating option was set
 test_override({expr}, {val})    none	test with Vim internal overrides
+test_scrollbar({which}, {value}, {dragging})
+				none	scroll in the GUI for testing
 test_settime({expr})		none	set current time for testing
 timer_info([{id}])		List	information about timers
 timer_pause({id}, {pause})	none	pause or unpause a timer
@@ -8773,6 +8775,23 @@
 <		The value of "starting" is saved.  It is restored by: >
 			call test_override('starting', 0)
 
+test_scrollbar({which}, {value}, {dragging})		*test_scrollbar()*
+		Pretend using scrollbar {which} to move it to position
+		{value}.  {which} can be:
+			left	Left scrollbar of the current window
+			right	Right scrollbar of the current window
+			hor	Horizontal scrollbar
+
+		For the vertical scrollbars {value} can be 1 to the
+		line-count of the buffer.  For the horizontal scrollbar the
+		{value} can be between 1 and the maximum line length, assuming
+		'wrap' is not set.
+
+		When {dragging} is non-zero it's like dragging the scrollbar,
+		otherwise it's like clicking in the scrollbar.
+		Only works when the {which} scrollbar actually exists,
+		obviously only when using the GUI.
+
 test_settime({expr})					*test_settime()*
 		Set the time Vim uses internally.  Currently only used for
 		timestamps in the history, as they are used in viminfo, and