patch 8.1.0815: dialog for file changed outside of Vim not tested

Problem:    Dialog for file changed outside of Vim not tested.
Solution:   Add a test.  Move FileChangedShell test.  Add 'L' flag to
            feedkeys().
diff --git a/src/testdir/test_filechanged.vim b/src/testdir/test_filechanged.vim
new file mode 100644
index 0000000..ab34420
--- /dev/null
+++ b/src/testdir/test_filechanged.vim
@@ -0,0 +1,146 @@
+" Tests for when a file was changed outside of Vim.
+
+func Test_FileChangedShell_reload()
+  if !has('unix')
+    return
+  endif
+  augroup testreload
+    au FileChangedShell Xchanged_r let g:reason = v:fcs_reason | let v:fcs_choice = 'reload'
+  augroup END
+  new Xchanged_r
+  call setline(1, 'reload this')
+  write
+  " Need to wait until the timestamp would change by at least a second.
+  sleep 2
+  silent !echo 'extra line' >>Xchanged_r
+  checktime
+  call assert_equal('changed', g:reason)
+  call assert_equal(2, line('$'))
+  call assert_equal('extra line', getline(2))
+
+  " Only triggers once
+  let g:reason = ''
+  checktime
+  call assert_equal('', g:reason)
+
+  " When deleted buffer is not reloaded
+  silent !rm Xchanged_r
+  let g:reason = ''
+  checktime
+  call assert_equal('deleted', g:reason)
+  call assert_equal(2, line('$'))
+  call assert_equal('extra line', getline(2))
+
+  " When recreated buffer is reloaded
+  call setline(1, 'buffer is changed')
+  silent !echo 'new line' >>Xchanged_r
+  let g:reason = ''
+  checktime
+  call assert_equal('conflict', g:reason)
+  call assert_equal(1, line('$'))
+  call assert_equal('new line', getline(1))
+
+  " Only mode changed
+  silent !chmod +x Xchanged_r
+  let g:reason = ''
+  checktime
+  call assert_equal('mode', g:reason)
+  call assert_equal(1, line('$'))
+  call assert_equal('new line', getline(1))
+
+  " Only time changed
+  sleep 2
+  silent !touch Xchanged_r
+  let g:reason = ''
+  checktime
+  call assert_equal('time', g:reason)
+  call assert_equal(1, line('$'))
+  call assert_equal('new line', getline(1))
+
+  if has('persistent_undo')
+    " With an undo file the reload can be undone and a change before the
+    " reload.
+    set undofile
+    call setline(2, 'before write')
+    write
+    call setline(2, 'after write')
+    sleep 2
+    silent !echo 'different line' >>Xchanged_r
+    let g:reason = ''
+    checktime
+    call assert_equal('conflict', g:reason)
+    call assert_equal(3, line('$'))
+    call assert_equal('before write', getline(2))
+    call assert_equal('different line', getline(3))
+    " undo the reload
+    undo
+    call assert_equal(2, line('$'))
+    call assert_equal('after write', getline(2))
+    " undo the change before reload
+    undo
+    call assert_equal(2, line('$'))
+    call assert_equal('before write', getline(2))
+
+    set noundofile
+  endif
+
+  au! testreload
+  bwipe!
+  call delete('Xchanged_r')
+endfunc
+
+func Test_file_changed_dialog()
+  if !has('unix')
+    return
+  endif
+  au! FileChangedShell
+
+  new Xchanged_d
+  call setline(1, 'reload this')
+  write
+  " Need to wait until the timestamp would change by at least a second.
+  sleep 2
+  silent !echo 'extra line' >>Xchanged_d
+  call feedkeys('L', 'L')
+  checktime
+  call assert_match('W11:', v:warningmsg)
+  call assert_equal(2, line('$'))
+  call assert_equal('reload this', getline(1))
+  call assert_equal('extra line', getline(2))
+
+  " delete buffer, only shows an error, no prompt
+  silent !rm Xchanged_d
+  checktime
+  call assert_match('E211:', v:warningmsg)
+  call assert_equal(2, line('$'))
+  call assert_equal('extra line', getline(2))
+
+  " Recreate buffer and reload
+  call setline(1, 'buffer is changed')
+  silent !echo 'new line' >Xchanged_d
+  call feedkeys('L', 'L')
+  checktime
+  call assert_match('W12:', v:warningmsg)
+  call assert_equal(1, line('$'))
+  call assert_equal('new line', getline(1))
+
+  " Only mode changed, reload
+  silent !chmod +x Xchanged_d
+  call feedkeys('L', 'L')
+  checktime
+  call assert_match('W16:', v:warningmsg)
+  call assert_equal(1, line('$'))
+  call assert_equal('new line', getline(1))
+
+  " Only time changed, no prompt
+  sleep 2
+  silent !touch Xchanged_d
+  let v:warningmsg = ''
+  checktime
+  call assert_equal('', v:warningmsg)
+  call assert_equal(1, line('$'))
+  call assert_equal('new line', getline(1))
+
+  bwipe!
+  call delete('Xchanged_d')
+endfunc