@BeforeClass
  public static void setUpClass() throws Exception {
    // Register Tink and the key manger, as a user would typically do if they add their own key
    // type.
    DeterministicAeadConfig.register();
    // Register the key manager the user would register. This has the type url TYPE_URL and
    // interprets the key as AesSivKey exactly as Tink would.
    Registry.registerKeyManager(new LegacyAesSivTestKeyManager(), true);
  }
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/daead/KeyManagerIntegrationTest.java