package encrypt

import (
	"bytes"
	"testing"
)

func TestAESGCMRoundTripAndRandomNonce(t *testing.T) {
	key := bytes.Repeat([]byte{7}, AESGCMKeySize)
	plain := []byte("message encryption key")
	aad := []byte("tenant:1:version:1")
	first, firstNonce, err := AESGCMEncrypt(plain, key, aad)
	if err != nil {
		t.Fatal(err)
	}
	second, secondNonce, err := AESGCMEncrypt(plain, key, aad)
	if err != nil {
		t.Fatal(err)
	}
	if bytes.Equal(firstNonce, secondNonce) || bytes.Equal(first, second) {
		t.Fatal("repeated encryption must use a different nonce and ciphertext")
	}
	decoded, err := AESGCMDecrypt(first, firstNonce, key, aad)
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(decoded, plain) {
		t.Fatalf("unexpected plaintext: %q", decoded)
	}
	first[0] ^= 1
	if _, err = AESGCMDecrypt(first, firstNonce, key, aad); err == nil {
		t.Fatal("tampered ciphertext must fail authentication")
	}
}