b, err := hex.DecodeString(s)
	if err != nil {
		panic(err)
	}
	return b
}

func returnBigZipBytes() (r io.ReaderAt, size int64) {
	b := biggestZipBytes()
	for i := 0; i < 2; i++ {
		r, err := NewReader(bytes.NewReader(b), int64(len(b)))
		if err != nil {
			panic(err)
		}
		f, err := r.File[0].Open()
		if err != nil {
			panic(err)
		}
		b, err = io.ReadAll(f)

func TestNegativeRead(t *testing.T) {
	// should panic with a description pointing at the reader, not at itself.
	// (should NOT panic with slice index error, for example.)
	b := NewReader(new(negativeReader))
	defer func() {
		switch err := recover().(type) {
		case nil:
			t.Fatal("read did not panic")
		case error:

				"application/onenote",
				"application/parityfec",
				"application/patch-ops-error+xml",
				"application/pgp-encrypted",
				"application/pgp-keys",
				"application/pgp-signature",
				"application/pics-rules",
				"application/pidf+xml",
				"application/pidf-diff+xml",
				"application/pkcs10",
				"application/pkcs7-mime",
				"application/pkcs7-signature",
				"application/pkix-cert",