message: test: external_signer wallet flag is immutable
diff: @@ -86,5 +86,10 @@ class SignerTest(BitcoinTestFramework):
  assert_equal(result['signers'][0]["fingerprint"], "00000001")
  assert_equal(result['signers'][0]["name"], "trezor_t")
  + # Flag can't be set afterwards (could be added later for non-blank descriptor based watch-only wallets)
  + self.nodes[1].createwallet(wallet_name='not_hww', disable_private_keys=True, descriptors=True, external_signer=False)
  + not_hww = self.nodes[1].get_wallet_rpc('not_hww')
  + assert_raises_rpc_error(-8, "Wallet flag is immutable: external_signer", not_hww.setwalletflag, "external_signer", True)
  +
  if __name__ == '__main__':
  SignerTest().main()
  