@Test
  public void testPoly1305() throws GeneralSecurityException {
    byte[] key =
        Hex.decode("" + "85d6be7857556d337f4452fe42d506a8" + "0103808afb0db2fd4abff6af4149f51b");
    byte[] in = ("Cryptographic Forum Research Group").getBytes(UTF_8);
    Truth.assertThat(Poly1305.computeMac(key, in))
        .isEqualTo(Hex.decode("" + "a8061dc1305136c6c22b8baf0c0127a9"));
  }
Tests against the test vectors in Section 2.5.2 of RFC 7539.
https://tools.ietf.org/html/rfc7539#section-2.5.2
java_src/src/test/java/com/google/crypto/tink/aead/internal/Poly1305Test.java