refactor: test/bench: dedup Build{Crediting,Spending}Transaction()

prototypes used in src/test/script_tests.cpp:
- CMutableTransaction BuildCreditingTransaction(const CScript& scriptPubKey, int nValue = 0);
- CMutableTransaction BuildSpendingTransaction(const CScript& scriptSig, const CScriptWitness& scriptWitness, const CTransaction& txCredit);

prototypes used in bench/verify_script.cpp:
- CMutableTransaction BuildCreditingTransaction(const CScript& scriptPubKey);
- CMutableTransaction BuildSpendingTransaction(const CScript& scriptSig, const CMutableTransaction& txCredit);

The more generic versions from the script tests are moved into a new file pair
transaction_utils.cpp/h and the calls are adapted accordingly in the
verify_script benchmark (passing the nValue of 1 explicitely for
BuildCreditingTransaction(), passing empty scriptWitness explicitely and
converting txCredit parameter to CTransaction in BuildSpendingTransaction()).

6 files changed, 66 insertions, 71 deletions

diff --git a/src/Makefile.bench.include b/src/Makefile.bench.include
index e421b377a0..38143e32b9 100644
--- a/src/Makefile.bench.include
+++ b/src/Makefile.bench.include
@@ -39,6 +39,8 @@ bench_bench_bitcoin_SOURCES = \
   bench/lockedpool.cpp \
   bench/poly1305.cpp \
   bench/prevector.cpp \
+  test/lib/transaction_utils.h \
+  test/lib/transaction_utils.cpp \
   test/setup_common.h \
   test/setup_common.cpp \
   test/util.h \
diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index 7292ca0784..3af55d9dab 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -53,6 +53,8 @@ RAW_TEST_FILES =
 GENERATED_TEST_FILES = $(JSON_TEST_FILES:.json=.json.h) $(RAW_TEST_FILES:.raw=.raw.h)
 
 BITCOIN_TEST_SUITE = \
+  test/lib/transaction_utils.h \
+  test/lib/transaction_utils.cpp \
   test/main.cpp \
   test/setup_common.h \
   test/setup_common.cpp
diff --git a/src/bench/verify_script.cpp b/src/bench/verify_script.cpp
index 4891c57b3a..c9947f192e 100644
--- a/src/bench/verify_script.cpp
+++ b/src/bench/verify_script.cpp
@@ -10,44 +10,10 @@
 #include <script/script.h>
 #include <script/standard.h>
 #include <streams.h>
+#include <test/lib/transaction_utils.h>
 
 #include <array>
 
-// FIXME: Dedup with BuildCreditingTransaction in test/script_tests.cpp.
-static CMutableTransaction BuildCreditingTransaction(const CScript& scriptPubKey)
-{
-    CMutableTransaction txCredit;
-    txCredit.nVersion = 1;
-    txCredit.nLockTime = 0;
-    txCredit.vin.resize(1);
-    txCredit.vout.resize(1);
-    txCredit.vin[0].prevout.SetNull();
-    txCredit.vin[0].scriptSig = CScript() << CScriptNum(0) << CScriptNum(0);
-    txCredit.vin[0].nSequence = CTxIn::SEQUENCE_FINAL;
-    txCredit.vout[0].scriptPubKey = scriptPubKey;
-    txCredit.vout[0].nValue = 1;
-
-    return txCredit;
-}
-
-// FIXME: Dedup with BuildSpendingTransaction in test/script_tests.cpp.
-static CMutableTransaction BuildSpendingTransaction(const CScript& scriptSig, const CMutableTransaction& txCredit)
-{
-    CMutableTransaction txSpend;
-    txSpend.nVersion = 1;
-    txSpend.nLockTime = 0;
-    txSpend.vin.resize(1);
-    txSpend.vout.resize(1);
-    txSpend.vin[0].prevout.hash = txCredit.GetHash();
-    txSpend.vin[0].prevout.n = 0;
-    txSpend.vin[0].scriptSig = scriptSig;
-    txSpend.vin[0].nSequence = CTxIn::SEQUENCE_FINAL;
-    txSpend.vout[0].scriptPubKey = CScript();
-    txSpend.vout[0].nValue = txCredit.vout[0].nValue;
-
-    return txSpend;
-}
-
 // Microbenchmark for verification of a basic P2WPKH script. Can be easily
 // modified to measure performance of other types of scripts.
 static void VerifyScriptBench(benchmark::State& state)
@@ -71,8 +37,8 @@ static void VerifyScriptBench(benchmark::State& state)
     CScript scriptPubKey = CScript() << witnessversion << ToByteVector(pubkeyHash);
     CScript scriptSig;
     CScript witScriptPubkey = CScript() << OP_DUP << OP_HASH160 << ToByteVector(pubkeyHash) << OP_EQUALVERIFY << OP_CHECKSIG;
-    const CMutableTransaction& txCredit = BuildCreditingTransaction(scriptPubKey);
-    CMutableTransaction txSpend = BuildSpendingTransaction(scriptSig, txCredit);
+    const CMutableTransaction& txCredit = BuildCreditingTransaction(scriptPubKey, 1);
+    CMutableTransaction txSpend = BuildSpendingTransaction(scriptSig, CScriptWitness(), CTransaction(txCredit));
     CScriptWitness& witness = txSpend.vin[0].scriptWitness;
     witness.stack.emplace_back();
     key.Sign(SignatureHash(witScriptPubkey, txSpend, 0, SIGHASH_ALL, txCredit.vout[0].nValue, SigVersion::WITNESS_V0), witness.stack.back());
diff --git a/src/test/lib/transaction_utils.cpp b/src/test/lib/transaction_utils.cpp
new file mode 100644
index 0000000000..2619fb9006
--- /dev/null
+++ b/src/test/lib/transaction_utils.cpp
@@ -0,0 +1,39 @@
+// Copyright (c) 2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <test/lib/transaction_utils.h>
+
+CMutableTransaction BuildCreditingTransaction(const CScript& scriptPubKey, int nValue)
+{
+    CMutableTransaction txCredit;
+    txCredit.nVersion = 1;
+    txCredit.nLockTime = 0;
+    txCredit.vin.resize(1);
+    txCredit.vout.resize(1);
+    txCredit.vin[0].prevout.SetNull();
+    txCredit.vin[0].scriptSig = CScript() << CScriptNum(0) << CScriptNum(0);
+    txCredit.vin[0].nSequence = CTxIn::SEQUENCE_FINAL;
+    txCredit.vout[0].scriptPubKey = scriptPubKey;
+    txCredit.vout[0].nValue = nValue;
+
+    return txCredit;
+}
+
+CMutableTransaction BuildSpendingTransaction(const CScript& scriptSig, const CScriptWitness& scriptWitness, const CTransaction& txCredit)
+{
+    CMutableTransaction txSpend;
+    txSpend.nVersion = 1;
+    txSpend.nLockTime = 0;
+    txSpend.vin.resize(1);
+    txSpend.vout.resize(1);
+    txSpend.vin[0].scriptWitness = scriptWitness;
+    txSpend.vin[0].prevout.hash = txCredit.GetHash();
+    txSpend.vin[0].prevout.n = 0;
+    txSpend.vin[0].scriptSig = scriptSig;
+    txSpend.vin[0].nSequence = CTxIn::SEQUENCE_FINAL;
+    txSpend.vout[0].scriptPubKey = CScript();
+    txSpend.vout[0].nValue = txCredit.vout[0].nValue;
+
+    return txSpend;
+}
diff --git a/src/test/lib/transaction_utils.h b/src/test/lib/transaction_utils.h
new file mode 100644
index 0000000000..6f297ac34f
--- /dev/null
+++ b/src/test/lib/transaction_utils.h
@@ -0,0 +1,19 @@
+// Copyright (c) 2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_TEST_LIB_TRANSACTION_UTILS_H
+#define BITCOIN_TEST_LIB_TRANSACTION_UTILS_H
+
+#include <primitives/transaction.h>
+
+// create crediting transaction
+// [1 coinbase input => 1 output with given scriptPubkey and value]
+CMutableTransaction BuildCreditingTransaction(const CScript& scriptPubKey, int nValue = 0);
+
+// create spending transaction
+// [1 input with referenced transaction outpoint, scriptSig, scriptWitness =>
+//  1 output with empty scriptPubKey, full value of referenced transaction]
+CMutableTransaction BuildSpendingTransaction(const CScript& scriptSig, const CScriptWitness& scriptWitness, const CTransaction& txCredit);
+
+#endif // BITCOIN_TEST_LIB_TRANSACTION_UTILS_H
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index 84a70fe78b..caa99805c3 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -12,6 +12,7 @@
 #include <script/signingprovider.h>
 #include <util/system.h>
 #include <util/strencodings.h>
+#include <test/lib/transaction_utils.h>
 #include <test/setup_common.h>
 #include <rpc/util.h>
 #include <streams.h>
@@ -121,40 +122,6 @@ static ScriptError_t ParseScriptError(const std::string &name)
 
 BOOST_FIXTURE_TEST_SUITE(script_tests, BasicTestingSetup)
 
-CMutableTransaction BuildCreditingTransaction(const CScript& scriptPubKey, int nValue = 0)
-{
-    CMutableTransaction txCredit;
-    txCredit.nVersion = 1;
-    txCredit.nLockTime = 0;
-    txCredit.vin.resize(1);
-    txCredit.vout.resize(1);
-    txCredit.vin[0].prevout.SetNull();
-    txCredit.vin[0].scriptSig = CScript() << CScriptNum(0) << CScriptNum(0);
-    txCredit.vin[0].nSequence = CTxIn::SEQUENCE_FINAL;
-    txCredit.vout[0].scriptPubKey = scriptPubKey;
-    txCredit.vout[0].nValue = nValue;
-
-    return txCredit;
-}
-
-CMutableTransaction BuildSpendingTransaction(const CScript& scriptSig, const CScriptWitness& scriptWitness, const CTransaction& txCredit)
-{
-    CMutableTransaction txSpend;
-    txSpend.nVersion = 1;
-    txSpend.nLockTime = 0;
-    txSpend.vin.resize(1);
-    txSpend.vout.resize(1);
-    txSpend.vin[0].scriptWitness = scriptWitness;
-    txSpend.vin[0].prevout.hash = txCredit.GetHash();
-    txSpend.vin[0].prevout.n = 0;
-    txSpend.vin[0].scriptSig = scriptSig;
-    txSpend.vin[0].nSequence = CTxIn::SEQUENCE_FINAL;
-    txSpend.vout[0].scriptPubKey = CScript();
-    txSpend.vout[0].nValue = txCredit.vout[0].nValue;
-
-    return txSpend;
-}
-
 void DoTest(const CScript& scriptPubKey, const CScript& scriptSig, const CScriptWitness& scriptWitness, int flags, const std::string& message, int scriptError, CAmount nValue = 0)
 {
     bool expect = (scriptError == SCRIPT_ERR_OK);