diff --git a/src/testdir/test_cursor_func.vim b/src/testdir/test_cursor_func.vim
index 3cdf4cb..2bdda86 100644
--- a/src/testdir/test_cursor_func.vim
+++ b/src/testdir/test_cursor_func.vim
@@ -206,6 +206,11 @@
   nmenu WinBar.TEST :
   call assert_equal(#{col: 1, row: 2, endcol: 1, curscol: 1}, screenpos(win_getid(), 1, 1))
   nunmenu WinBar.TEST
+  call assert_equal(#{col: 1, row: 1, endcol: 1, curscol: 1}, screenpos(win_getid(), 1, 1))
+
+  call assert_equal(#{col: 0, row: 0, endcol: 0, curscol: 0}, screenpos(0, 0, 1))
+  call assert_equal(#{col: 0, row: 0, endcol: 0, curscol: 0}, screenpos(0, -1, 1))
+  call assert_equal(#{col: 1, row: 1, endcol: 1, curscol: 1}, screenpos(0, 1, -v:maxcol))
 endfunc
 
 func Test_screenpos_fold()