if b.Len() != len(c) {
		t.Errorf("%s: len=%d, want %d", f.Name, b.Len(), len(c))
		return
	}

	for i, b := range b.Bytes() {
		if b != c[i] {
			t.Errorf("%s: content[%d]=%q want %q", f.Name, i, b, c[i])
			return
		}
	}
}

func testFileMode(t *testing.T, f *File, want fs.FileMode) {
	mode := f.Mode()
	if want == 0 {
		t.Errorf("%s mode: got %v, want none", f.Name, mode)
	} else if mode != want {