@BeforeClass
  public static void setUpClass() throws Exception {
    // We register Tink and key manger, as a user would typically do if they add their own key type.
    SignatureConfig.register();
    // Register the key managers the user would register. These have type URLs PRIVATE_TYPE_URL and
    // PUBLIC_TYPE_URL, and interpret the keys as Ed25519PrivateKey and Ed25519PublicKey exactly
    // as Tink would.
    Registry.registerKeyManager(new LegacyPublicKeySignKeyManager(), true);
    Registry.registerKeyManager(new LegacyPublicKeyVerifyKeyManager(), false);

    publicKeyByteArray =
        Hex.decode("ea42941a6dc801484390b2955bc7376d172eeb72640a54e5b50c95efa2fc6ad8");
    privateKeyByteArray =
        Hex.decode("9cac7d19aeecc563a3dff7bcae0fbbbc28087b986c49a3463077dd5281437e81");
  }
This test attempts to test the case where a user registers their own key type with
Registry.registerKeyManager() and then uses it.
java_src/src/test/java/com/google/crypto/tink/signature/KeyManagerIntegrationTest.java