refactor: move SignSignature helpers to test utils

These helpers haven't been used in production code since segwit was
merged more than eight years ago (see commit 605e8473, PR #8149),
so it seems appropriate to move them to the test utils module.

Can be reviewed via `--color-moved=dimmed-zebra`.

src/script/sign.cpp

@@ -694,27 +694,6 @@ void SignatureData::MergeSignatureData(SignatureData sigdata)
     signatures.insert(std::make_move_iterator(sigdata.signatures.begin()), std::make_move_iterator(sigdata.signatures.end()));
 }
 
-bool SignSignature(const SigningProvider &provider, const CScript& fromPubKey, CMutableTransaction& txTo, unsigned int nIn, const CAmount& amount, int nHashType, SignatureData& sig_data)
-{
-    assert(nIn < txTo.vin.size());
-
-    MutableTransactionSignatureCreator creator(txTo, nIn, amount, nHashType);
-
-    bool ret = ProduceSignature(provider, creator, fromPubKey, sig_data);
-    UpdateInput(txTo.vin.at(nIn), sig_data);
-    return ret;
-}
-
-bool SignSignature(const SigningProvider &provider, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType, SignatureData& sig_data)
-{
-    assert(nIn < txTo.vin.size());
-    const CTxIn& txin = txTo.vin[nIn];
-    assert(txin.prevout.n < txFrom.vout.size());
-    const CTxOut& txout = txFrom.vout[txin.prevout.n];
-
-    return SignSignature(provider, txout.scriptPubKey, txTo, nIn, txout.nValue, nHashType, sig_data);
-}
-
 namespace {
 /** Dummy signature checker which accepts all signatures. */
 class DummySignatureChecker final : public BaseSignatureChecker

src/script/sign.h

@@ -97,25 +97,6 @@ struct SignatureData {
 /** Produce a script signature using a generic signature creator. */
 bool ProduceSignature(const SigningProvider& provider, const BaseSignatureCreator& creator, const CScript& scriptPubKey, SignatureData& sigdata);
 
-/**
- * Produce a satisfying script (scriptSig or witness).
- *
- * @param provider   Utility containing the information necessary to solve a script.
- * @param fromPubKey The script to produce a satisfaction for.
- * @param txTo       The spending transaction.
- * @param nIn        The index of the input in `txTo` referring the output being spent.
- * @param amount     The value of the output being spent.
- * @param nHashType  Signature hash type.
- * @param sig_data   Additional data provided to solve a script. Filled with the resulting satisfying
- *                   script and whether the satisfaction is complete.
- *
- * @return           True if the produced script is entirely satisfying `fromPubKey`.
- **/
-bool SignSignature(const SigningProvider &provider, const CScript& fromPubKey, CMutableTransaction& txTo,
-                   unsigned int nIn, const CAmount& amount, int nHashType, SignatureData& sig_data);
-bool SignSignature(const SigningProvider &provider, const CTransaction& txFrom, CMutableTransaction& txTo,
-                   unsigned int nIn, int nHashType, SignatureData& sig_data);
-
 /** Extract signature data from a transaction input, and insert it. */
 SignatureData DataFromTransaction(const CMutableTransaction& tx, unsigned int nIn, const CTxOut& txout);
 void UpdateInput(CTxIn& input, const SignatureData& data);

src/test/fuzz/script_sign.cpp

@@ -13,6 +13,7 @@
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
 #include <test/fuzz/util.h>
+#include <test/util/transaction_utils.h>
 #include <util/chaintype.h>
 #include <util/translation.h>
 

src/test/multisig_tests.cpp

@@ -10,6 +10,7 @@
 #include <script/sign.h>
 #include <script/signingprovider.h>
 #include <test/util/setup_common.h>
+#include <test/util/transaction_utils.h>
 #include <tinyformat.h>
 #include <uint256.h>
 

src/test/script_p2sh_tests.cpp

@@ -11,6 +11,7 @@
 #include <script/sign.h>
 #include <script/signingprovider.h>
 #include <test/util/setup_common.h>
+#include <test/util/transaction_utils.h>
 #include <validation.h>
 
 #include <vector>

src/test/util/transaction_utils.cpp

@@ -90,3 +90,24 @@ void BulkTransaction(CMutableTransaction& tx, int32_t target_weight)
     assert(GetTransactionWeight(CTransaction(tx)) >= target_weight);
     assert(GetTransactionWeight(CTransaction(tx)) <= target_weight + 3);
 }
+
+bool SignSignature(const SigningProvider &provider, const CScript& fromPubKey, CMutableTransaction& txTo, unsigned int nIn, const CAmount& amount, int nHashType, SignatureData& sig_data)
+{
+    assert(nIn < txTo.vin.size());
+
+    MutableTransactionSignatureCreator creator(txTo, nIn, amount, nHashType);
+
+    bool ret = ProduceSignature(provider, creator, fromPubKey, sig_data);
+    UpdateInput(txTo.vin.at(nIn), sig_data);
+    return ret;
+}
+
+bool SignSignature(const SigningProvider &provider, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType, SignatureData& sig_data)
+{
+    assert(nIn < txTo.vin.size());
+    const CTxIn& txin = txTo.vin[nIn];
+    assert(txin.prevout.n < txFrom.vout.size());
+    const CTxOut& txout = txFrom.vout[txin.prevout.n];
+
+    return SignSignature(provider, txout.scriptPubKey, txTo, nIn, txout.nValue, nHashType, sig_data);
+}

src/test/util/transaction_utils.h

@@ -6,6 +6,7 @@
 #define BITCOIN_TEST_UTIL_TRANSACTION_UTILS_H
 
 #include <primitives/transaction.h>
+#include <script/sign.h>
 
 #include <array>
 
@@ -30,4 +31,23 @@ std::vector<CMutableTransaction> SetupDummyInputs(FillableSigningProvider& keyst
 // by appending a single output with padded output script
 void BulkTransaction(CMutableTransaction& tx, int32_t target_weight);
 
+/**
+ * Produce a satisfying script (scriptSig or witness).
+ *
+ * @param provider   Utility containing the information necessary to solve a script.
+ * @param fromPubKey The script to produce a satisfaction for.
+ * @param txTo       The spending transaction.
+ * @param nIn        The index of the input in `txTo` referring the output being spent.
+ * @param amount     The value of the output being spent.
+ * @param nHashType  Signature hash type.
+ * @param sig_data   Additional data provided to solve a script. Filled with the resulting satisfying
+ *                   script and whether the satisfaction is complete.
+ *
+ * @return           True if the produced script is entirely satisfying `fromPubKey`.
+ **/
+bool SignSignature(const SigningProvider &provider, const CScript& fromPubKey, CMutableTransaction& txTo,
+                   unsigned int nIn, const CAmount& amount, int nHashType, SignatureData& sig_data);
+bool SignSignature(const SigningProvider &provider, const CTransaction& txFrom, CMutableTransaction& txTo,
+                   unsigned int nIn, int nHashType, SignatureData& sig_data);
+
 #endif // BITCOIN_TEST_UTIL_TRANSACTION_UTILS_H