func (issue12991File) Stat() (fs.FileInfo, error) { return nil, fs.ErrPermission }
func (issue12991File) Close() error               { return nil }

func TestFileServerErrorMessages(t *testing.T) { run(t, testFileServerErrorMessages) }
func testFileServerErrorMessages(t *testing.T, mode testMode) {
	fs := fakeFS{
		"/500": &fakeFileInfo{
			err: errors.New("random error"),
		},
		"/403": &fakeFileInfo{