message: fuzz: Extend psbt fuzz target a bit
diff: // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  +#include <test/fuzz/FuzzedDataProvider.h>
  #include <test/fuzz/fuzz.h>
  #include <node/psbt.h>
  #include <pubkey.h>
  #include <script/script.h>
  #include <streams.h>
  +#include <util/check.h>
  #include <version.h>
  #include <cstdint>
  @@ -23,10 +25,10 @@ void initialize_psbt()
  FUZZ_TARGET_INIT(psbt, initialize_psbt)
  {
  + FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
  PartiallySignedTransaction psbt_mut;
  - const std::string raw_psbt{buffer.begin(), buffer.end()};
  std::string error;
  - if (!DecodeRawPSBT(psbt_mut, raw_psbt, error)) {
  + if (!DecodeRawPSBT(psbt_mut, fuzzed_data_provider.ConsumeRandomLengthString(), error)) {
  return;
  }
  const PartiallySignedTransaction psbt = psbt_mut;
  @@ -49,6 +51,7 @@ FUZZ_TARGET_INIT(psbt, initialize_psbt)
  (void)PSBTInputSigned(input);
  (void)input.IsNull();
  }
  + (void)CountPSBTUnsignedInputs(psbt);
  for (const PSBTOutput& output : psbt.outputs) {
  (void)output.IsNull();
  @@ -71,6 +74,20 @@ FUZZ_TARGET_INIT(psbt, initialize_psbt)
  const PartiallySignedTransaction psbt_from_tx{result};
  }
  + PartiallySignedTransaction psbt_merge;
  + if (!DecodeRawPSBT(psbt_merge, fuzzed_data_provider.ConsumeRandomLengthString(), error)) {
  + psbt_merge = psbt;
  + }
  + psbt_mut = psbt;
  + (void)psbt_mut.Merge(psbt_merge);
  + psbt_mut = psbt;
  + (void)CombinePSBTs(psbt_mut, {psbt_mut, psbt_merge});
  psbt_mut = psbt;
  - (void)psbt_mut.Merge(psbt);
  + for (unsigned int i = 0; i < psbt_merge.tx->vin.size(); ++i) {
  + (void)psbt_mut.AddInput(psbt_merge.tx->vin[i], psbt_merge.inputs[i]);
  + }
  + for (unsigned int i = 0; i < psbt_merge.tx->vout.size(); ++i) {
  + Assert(psbt_mut.AddOutput(psbt_merge.tx->vout[i], psbt_merge.outputs[i]));
  + }
  + psbt_mut.unknown.insert(psbt_merge.unknown.begin(), psbt_merge.unknown.end());
  }
  