diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index 1a05a59..af07a64 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -2947,4 +2947,15 @@
   endif
 endfunc
 
+" Test for virtcol()
+func Test_virtcol()
+  enew!
+  call setline(1, "the\tquick\tbrown\tfox")
+  norm! 4|
+  call assert_equal(8, virtcol('.'))
+  call assert_equal(8, virtcol('.', v:false))
+  call assert_equal([4, 8], virtcol('.', v:true))
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/testdir/test_vim9_builtin.vim b/src/testdir/test_vim9_builtin.vim
index 4f39ebb..e83e320 100644
--- a/src/testdir/test_vim9_builtin.vim
+++ b/src/testdir/test_vim9_builtin.vim
@@ -4494,14 +4494,23 @@
 enddef
 
 def Test_virtcol()
-  v9.CheckDefAndScriptFailure(['virtcol(1.1)'], ['E1013: Argument 1: type mismatch, expected string but got float', 'E1222: String or List required for argument 1'])
-  v9.CheckDefExecAndScriptFailure(['virtcol("")'], 'E1209: Invalid value for a line number')
+  v9.CheckDefAndScriptFailure(['virtcol(1.1)'], [
+    'E1013: Argument 1: type mismatch, expected string but got float',
+    'E1222: String or List required for argument 1'])
+  v9.CheckDefAndScriptFailure(['virtcol(".", "a")'], [
+    'E1013: Argument 2: type mismatch, expected bool but got string',
+    'E1212: Bool required for argument 2'])
+  v9.CheckDefExecAndScriptFailure(['virtcol("")'],
+    'E1209: Invalid value for a line number')
   new
-  setline(1, ['abcdefgh'])
+  setline(1, ['abcde和平fgh'])
   cursor(1, 4)
   assert_equal(4, virtcol('.'))
+  assert_equal([4, 4], virtcol('.', 1))
+  cursor(1, 6)
+  assert_equal([6, 7], virtcol('.', 1))
   assert_equal(4, virtcol([1, 4]))
-  assert_equal(9, virtcol([1, '$']))
+  assert_equal(13, virtcol([1, '$']))
   assert_equal(0, virtcol([10, '$']))
   bw!
 enddef