code: public void authenticationSucceeds() {
      if (pendingCallback == null) {
        throw new IllegalStateException("No active fingerprint authentication request.");
      }
  
      AuthenticationResult result;
      if (RuntimeEnvironment.getApiLevel() >= N_MR1) {
        result = new AuthenticationResult(pendingCryptoObject, null, 0);
      } else {
        result = ReflectionHelpers.callConstructor(AuthenticationResult.class,
            ClassParameter.from(CryptoObject.class, pendingCryptoObject),
            ClassParameter.from(Fingerprint.class, null));
      }
  
      pendingCallback.onAuthenticationSucceeded(result);
    }
docs: Simulates a successful fingerprint authentication. An authentication request must have been
  issued with {@link FingerprintManager#authenticate(CryptoObject, CancellationSignal, int, AuthenticationCallback, Handler)} and not cancelled.