Merge bitcoin/bitcoin#32675: test: wallet: cover wallet passphrase with a null char

7cfbb85 test: wallet: cover wallet passphrase with a null char (brunoerg)

Pull request description:

  This PR adds test coverage for the `walletpassphrase`/`walletpassphrasechange` RPC when the passphrase is incorrect due to a null character.

  For reference: bitcoin/bitcoin#27068 introduced the usage of `SecureString` to allow null characters.

ACKs for top commit:
  maflcko:
    lgtm ACK 7cfbb85
  achow101:
    ACK 7cfbb85
  w0xlt:
    Code review ACK bitcoin/bitcoin@7cfbb85
  BrandonOdiwuor:
    Code Review ACK 7cfbb85
  theStack:
    ACK 7cfbb85
  pablomartin4btc:
    cr ACK 7cfbb85

Tree-SHA512: ecdb48662ceb6c55c4b301ca7f537c3159ece7b66ee40ea977583ffb74bd3d06e334ab3a5639a9cde3aa6443129f412f9aea0ee5a8b73b31dba0728d0890b7f1

Author: achow101

test/functional/wallet_encryption.py

@@ -95,6 +95,9 @@ def run_test(self):
         self.nodes[0].walletpassphrasechange(passphrase2, passphrase_with_nulls)
         # walletpassphrasechange should not stop at null characters
         assert_raises_rpc_error(-14, "wallet passphrase entered was incorrect", self.nodes[0].walletpassphrase, passphrase_with_nulls.partition("\0")[0], 10)
+        assert_raises_rpc_error(-14, "The wallet passphrase entered was incorrect", self.nodes[0].walletpassphrasechange, passphrase_with_nulls.partition("\0")[0], "abc")
+        assert_raises_rpc_error(-14, "wallet passphrase entered is incorrect. It contains a null character (ie - a zero byte)", self.nodes[0].walletpassphrase, passphrase_with_nulls + "\0", 10)
+        assert_raises_rpc_error(-14, "The old wallet passphrase entered is incorrect. It contains a null character (ie - a zero byte)", self.nodes[0].walletpassphrasechange, passphrase_with_nulls + "\0", "abc")
         with WalletUnlock(self.nodes[0], passphrase_with_nulls):
             sig = self.nodes[0].signmessage(address, msg)
             assert self.nodes[0].verifymessage(address, sig, msg)