diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index e31e2ed..4672fc0 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -2562,6 +2562,75 @@
   call assert_equal("\<M-F2>", getchar(0))
   call assert_equal(0, getchar(0))
 
+  call feedkeys("\<Tab>", '')
+  call assert_equal(char2nr("\<Tab>"), getchar())
+  call feedkeys("\<Tab>", '')
+  call assert_equal(char2nr("\<Tab>"), getchar(-1))
+  call feedkeys("\<Tab>", '')
+  call assert_equal(char2nr("\<Tab>"), getchar(-1, {}))
+  call feedkeys("\<Tab>", '')
+  call assert_equal(char2nr("\<Tab>"), getchar(-1, #{number: v:true}))
+  call assert_equal(0, getchar(0))
+  call assert_equal(0, getchar(1))
+  call assert_equal(0, getchar(0, #{number: v:true}))
+  call assert_equal(0, getchar(1, #{number: v:true}))
+
+  call feedkeys("\<Tab>", '')
+  call assert_equal("\<Tab>", getcharstr())
+  call feedkeys("\<Tab>", '')
+  call assert_equal("\<Tab>", getcharstr(-1))
+  call feedkeys("\<Tab>", '')
+  call assert_equal("\<Tab>", getcharstr(-1, {}))
+  call feedkeys("\<Tab>", '')
+  call assert_equal("\<Tab>", getchar(-1, #{number: v:false}))
+  call assert_equal('', getcharstr(0))
+  call assert_equal('', getcharstr(1))
+  call assert_equal('', getchar(0, #{number: v:false}))
+  call assert_equal('', getchar(1, #{number: v:false}))
+
+  for key in ["C-I", "C-X", "M-x"]
+    let lines =<< eval trim END
+      call feedkeys("\<*{key}>", '')
+      call assert_equal(char2nr("\<{key}>"), getchar())
+      call feedkeys("\<*{key}>", '')
+      call assert_equal(char2nr("\<{key}>"), getchar(-1))
+      call feedkeys("\<*{key}>", '')
+      call assert_equal(char2nr("\<{key}>"), getchar(-1, {{}}))
+      call feedkeys("\<*{key}>", '')
+      call assert_equal(char2nr("\<{key}>"), getchar(-1, {{'number': 1}}))
+      call feedkeys("\<*{key}>", '')
+      call assert_equal(char2nr("\<{key}>"), getchar(-1, {{'simplify': 1}}))
+      call feedkeys("\<*{key}>", '')
+      call assert_equal("\<*{key}>", getchar(-1, {{'simplify': v:false}}))
+      call assert_equal(0, getchar(0))
+      call assert_equal(0, getchar(1))
+    END
+    call v9.CheckLegacyAndVim9Success(lines)
+
+    let lines =<< eval trim END
+      call feedkeys("\<*{key}>", '')
+      call assert_equal("\<{key}>", getcharstr())
+      call feedkeys("\<*{key}>", '')
+      call assert_equal("\<{key}>", getcharstr(-1))
+      call feedkeys("\<*{key}>", '')
+      call assert_equal("\<{key}>", getcharstr(-1, {{}}))
+      call feedkeys("\<*{key}>", '')
+      call assert_equal("\<{key}>", getchar(-1, {{'number': 0}}))
+      call feedkeys("\<*{key}>", '')
+      call assert_equal("\<{key}>", getcharstr(-1, {{'simplify': 1}}))
+      call feedkeys("\<*{key}>", '')
+      call assert_equal("\<*{key}>", getcharstr(-1, {{'simplify': v:false}}))
+      call assert_equal('', getcharstr(0))
+      call assert_equal('', getcharstr(1))
+    END
+    call v9.CheckLegacyAndVim9Success(lines)
+  endfor
+
+  call assert_fails('call getchar(1, 1)', 'E1206:')
+  call assert_fails('call getcharstr(1, 1)', 'E1206:')
+  call assert_fails('call getcharstr(1, #{number: v:true})', 'E475:')
+  call assert_fails('call getcharstr(1, #{number: v:false})', 'E475:')
+
   call setline(1, 'xxxx')
   call test_setmouse(1, 3)
   let v:mouse_win = 9