fullblocktests, testhelper: refactor out spendableOut

spendableOut and the functions related to it are is moved to package testhelper and are exported. This is done to make the code reusable without introducing an import cycle when the testing code for invalidateblock and reconsiderblock are added in follow up commits.
btcsuite · kcalvinalvin · Apr 2, 2024 · Apr 2, 2024 · Apr 2, 2024 · Apr 2, 2024
commit 337d7f6be8cddca2c75589e5d9c5edcc5cce42fb
diff --git a/blockchain/fullblocktests/generate.go b/blockchain/fullblocktests/generate.go
@@ -19,6 +19,7 @@ import (
 	"time"
 
 	"github.com/btcsuite/btcd/blockchain"
+	"github.com/btcsuite/btcd/blockchain/internal/testhelper"
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
@@ -165,31 +166,6 @@ type BlockDisconnectExpectUTXO struct {
 // This implements the TestInstance interface.
 func (b BlockDisconnectExpectUTXO) FullBlockTestInstance() {}
 
-// spendableOut represents a transaction output that is spendable along with
-// additional metadata such as the block its in and how much it pays.
-type spendableOut struct {
-	prevOut wire.OutPoint
-	amount  btcutil.Amount
-}
-
-// makeSpendableOutForTx returns a spendable output for the given transaction
-// and transaction output index within the transaction.
-func makeSpendableOutForTx(tx *wire.MsgTx, txOutIndex uint32) spendableOut {
-	return spendableOut{
-		prevOut: wire.OutPoint{
-			Hash:  tx.TxHash(),
-			Index: txOutIndex,
-		},
-		amount: btcutil.Amount(tx.TxOut[txOutIndex].Value),
-	}
-}
-
-// makeSpendableOut returns a spendable output for the given block, transaction
-// index within the block, and transaction output index within the transaction.
-func makeSpendableOut(block *wire.MsgBlock, txIndex, txOutIndex uint32) spendableOut {
-	return makeSpendableOutForTx(block.Transactions[txIndex], txOutIndex)
-}
-
 // testGenerator houses state used to easy the process of generating test blocks
 // that build from one another along with housing other useful things such as
 // available spendable outputs used throughout the tests.
@@ -203,7 +179,7 @@ type testGenerator struct {
 	blockHeights map[string]int32
 
 	// Used for tracking spendable coinbase outputs.
-	spendableOuts     []spendableOut
+	spendableOuts     []testhelper.SpendableOut
 	prevCollectedHash chainhash.Hash
 
 	// Common key for any tests which require signed transactions.
@@ -449,14 +425,14 @@ func additionalTx(tx *wire.MsgTx) func(*wire.MsgBlock) {
 // transaction ends up with a unique hash.  The script is a simple OP_TRUE
 // script which avoids the need to track addresses and signature scripts in the
 // tests.
-func createSpendTx(spend *spendableOut, fee btcutil.Amount) *wire.MsgTx {
+func createSpendTx(spend *testhelper.SpendableOut, fee btcutil.Amount) *wire.MsgTx {
 	spendTx := wire.NewMsgTx(1)
 	spendTx.AddTxIn(&wire.TxIn{
-		PreviousOutPoint: spend.prevOut,
+		PreviousOutPoint: spend.PrevOut,
 		Sequence:         wire.MaxTxInSequenceNum,
 		SignatureScript:  nil,
 	})
-	spendTx.AddTxOut(wire.NewTxOut(int64(spend.amount-fee),
+	spendTx.AddTxOut(wire.NewTxOut(int64(spend.Amount-fee),
 		opTrueScript))
 	spendTx.AddTxOut(wire.NewTxOut(0, uniqueOpReturnScript()))
 
@@ -469,7 +445,7 @@ func createSpendTx(spend *spendableOut, fee btcutil.Amount) *wire.MsgTx {
 // is a simple OP_TRUE script which avoids the need to track addresses and
 // signature scripts in the tests.  The signature script is nil.
 func createSpendTxForTx(tx *wire.MsgTx, fee btcutil.Amount) *wire.MsgTx {
-	spend := makeSpendableOutForTx(tx, 0)
+	spend := testhelper.MakeSpendableOutForTx(tx, 0)
 	return createSpendTx(&spend, fee)
 }
 
@@ -492,7 +468,7 @@ func createSpendTxForTx(tx *wire.MsgTx, fee btcutil.Amount) *wire.MsgTx {
 // applied after all munge functions have been invoked:
 // - The merkle root will be recalculated unless it was manually changed
 // - The block will be solved unless the nonce was changed
-func (g *testGenerator) nextBlock(blockName string, spend *spendableOut, mungers ...func(*wire.MsgBlock)) *wire.MsgBlock {
+func (g *testGenerator) nextBlock(blockName string, spend *testhelper.SpendableOut, mungers ...func(*wire.MsgBlock)) *wire.MsgBlock {
 	// Create coinbase transaction for the block using any additional
 	// subsidy if specified.
 	nextHeight := g.tipHeight + 1
@@ -594,7 +570,7 @@ func (g *testGenerator) setTip(blockName string) {
 
 // oldestCoinbaseOuts removes the oldest coinbase output that was previously
 // saved to the generator and returns the set as a slice.
-func (g *testGenerator) oldestCoinbaseOut() spendableOut {
+func (g *testGenerator) oldestCoinbaseOut() testhelper.SpendableOut {
 	op := g.spendableOuts[0]
 	g.spendableOuts = g.spendableOuts[1:]
 	return op
@@ -603,7 +579,7 @@ func (g *testGenerator) oldestCoinbaseOut() spendableOut {
 // saveTipCoinbaseOut adds the coinbase tx output in the current tip block to
 // the list of spendable outputs.
 func (g *testGenerator) saveTipCoinbaseOut() {
-	g.spendableOuts = append(g.spendableOuts, makeSpendableOut(g.tip, 0, 0))
+	g.spendableOuts = append(g.spendableOuts, testhelper.MakeSpendableOut(g.tip, 0, 0))
 	g.prevCollectedHash = g.tip.BlockHash()
 }
 
@@ -947,7 +923,7 @@ func Generate(includeLargeReorg bool) (tests [][]TestInstance, err error) {
 	tests = append(tests, testInstances)
 
 	// Collect spendable outputs.  This simplifies the code below.
-	var outs []*spendableOut
+	var outs []*testhelper.SpendableOut
 	for i := uint16(0); i < coinbaseMaturity; i++ {
 		op := g.oldestCoinbaseOut()
 		outs = append(outs, &op)
@@ -985,7 +961,7 @@ func Generate(includeLargeReorg bool) (tests [][]TestInstance, err error) {
 	//               \-> b3(1)
 	g.setTip("b1")
 	g.nextBlock("b3", outs[1])
-	b3Tx1Out := makeSpendableOut(g.tip, 1, 0)
+	b3Tx1Out := testhelper.MakeSpendableOut(g.tip, 1, 0)
 	acceptedToSideChainWithExpectedTip("b2")
 
 	// Extend b3 fork to make the alternative chain longer and force reorg.
@@ -1300,7 +1276,7 @@ func Generate(includeLargeReorg bool) (tests [][]TestInstance, err error) {
 	g.setTip("b35")
 	doubleSpendTx := createSpendTx(outs[11], lowFee)
 	g.nextBlock("b37", outs[11], additionalTx(doubleSpendTx))
-	b37Tx1Out := makeSpendableOut(g.tip, 1, 0)
+	b37Tx1Out := testhelper.MakeSpendableOut(g.tip, 1, 0)
 	rejected(blockchain.ErrMissingTxOut)
 
 	g.setTip("b35")
@@ -1356,7 +1332,7 @@ func Generate(includeLargeReorg bool) (tests [][]TestInstance, err error) {
 		for i := 0; i < txnsNeeded; i++ {
 			// Create a signed transaction that spends from the
 			// associated p2sh output in b39.
-			spend := makeSpendableOutForTx(b39.Transactions[i+2], 2)
+			spend := testhelper.MakeSpendableOutForTx(b39.Transactions[i+2], 2)
 			tx := createSpendTx(&spend, lowFee)
 			sig, err := txscript.RawTxInSignature(tx, 0,
 				redeemScript, txscript.SigHashAll, g.privKey)
@@ -1387,7 +1363,7 @@ func Generate(includeLargeReorg bool) (tests [][]TestInstance, err error) {
 	g.nextBlock("b41", outs[12], func(b *wire.MsgBlock) {
 		txnsNeeded := (maxBlockSigOps / redeemScriptSigOps)
 		for i := 0; i < txnsNeeded; i++ {
-			spend := makeSpendableOutForTx(b39.Transactions[i+2], 2)
+			spend := testhelper.MakeSpendableOutForTx(b39.Transactions[i+2], 2)
 			tx := createSpendTx(&spend, lowFee)
 			sig, err := txscript.RawTxInSignature(tx, 0,
 				redeemScript, txscript.SigHashAll, g.privKey)
@@ -1719,7 +1695,7 @@ func Generate(includeLargeReorg bool) (tests [][]TestInstance, err error) {
 	//                 \-> b59(17)
 	g.setTip("b57")
 	g.nextBlock("b59", outs[17], func(b *wire.MsgBlock) {
-		b.Transactions[1].TxOut[0].Value = int64(outs[17].amount) + 1
+		b.Transactions[1].TxOut[0].Value = int64(outs[17].Amount) + 1
 	})
 	rejected(blockchain.ErrSpendTooHigh)
 
@@ -2003,14 +1979,14 @@ func Generate(includeLargeReorg bool) (tests [][]TestInstance, err error) {
 		// NOTE: The createSpendTx func adds the OP_RETURN output.
 		zeroFee := btcutil.Amount(0)
 		for i := uint32(0); i < numAdditionalOutputs; i++ {
-			spend := makeSpendableOut(b, 1, i+2)
+			spend := testhelper.MakeSpendableOut(b, 1, i+2)
 			tx := createSpendTx(&spend, zeroFee)
 			b.AddTransaction(tx)
 		}
 	})
 	g.assertTipBlockNumTxns(6)
 	g.assertTipBlockTxOutOpReturn(5, 1)
-	b75OpReturnOut := makeSpendableOut(g.tip, 5, 1)
+	b75OpReturnOut := testhelper.MakeSpendableOut(g.tip, 5, 1)
 	accepted()
 
 	// Reorg to a side chain that does not contain the OP_RETURNs.
@@ -2043,7 +2019,7 @@ func Generate(includeLargeReorg bool) (tests [][]TestInstance, err error) {
 	// An OP_RETURN output doesn't have any value and the default behavior
 	// of nextBlock is to assign a fee of one, so increment the amount here
 	// to effective negate that behavior.
-	b75OpReturnOut.amount++
+	b75OpReturnOut.Amount++
 	g.nextBlock("b80", &b75OpReturnOut)
 	rejected(blockchain.ErrMissingTxOut)
 
@@ -2075,7 +2051,7 @@ func Generate(includeLargeReorg bool) (tests [][]TestInstance, err error) {
 	g.nextBlock("b82a", outs[28])
 	accepted()
 
-	b82aTx1Out0 := makeSpendableOut(g.tip, 1, 0)
+	b82aTx1Out0 := testhelper.MakeSpendableOut(g.tip, 1, 0)
 	g.nextBlock("b83a", &b82aTx1Out0)
 	accepted()
 
@@ -2097,17 +2073,17 @@ func Generate(includeLargeReorg bool) (tests [][]TestInstance, err error) {
 	// We expect b82a output to now be a utxo since b83a was spending it and it was
 	// removed from the main chain.
 	blockDisconnectExpectUTXO("b82aTx1Out0",
-		true, b82aTx1Out0.prevOut, g.blocksByName["b83a"].BlockHash())
+		true, b82aTx1Out0.PrevOut, g.blocksByName["b83a"].BlockHash())
 
 	// We expect the output from b82 to not exist once b82a itself has been removed
 	// from the main chain.
 	blockDisconnectExpectUTXO("b82aTx1Out0",
-		false, b82aTx1Out0.prevOut, g.blocksByName["b82a"].BlockHash())
+		false, b82aTx1Out0.PrevOut, g.blocksByName["b82a"].BlockHash())
 
 	// The output that was being spent in b82a should exist after the removal of
 	// b82a.
 	blockDisconnectExpectUTXO("outs[28]",
-		true, outs[28].prevOut, g.blocksByName["b82a"].BlockHash())
+		true, outs[28].PrevOut, g.blocksByName["b82a"].BlockHash())
 
 	// Create block 84 and reorg out the sidechain with b83a as the tip.
 	//

diff --git a/blockchain/internal/testhelper/README.md b/blockchain/internal/testhelper/README.md
@@ -0,0 +1,16 @@
+testhelper
+==========
+
+[![Build Status](https://github.com/btcsuite/btcd/workflows/Build%20and%20Test/badge.svg)](https://github.com/btcsuite/btcd/actions)
+[![ISC License](http://img.shields.io/badge/license-ISC-blue.svg)](http://copyfree.org)
+[![GoDoc](https://img.shields.io/badge/godoc-reference-blue.svg)](https://pkg.go.dev/github.com/btcsuite/btcd/blockchain/testhelper)
+
+Package testhelper provides functions that are used internally in the
+btcd/blockchain and btcd/blockchain/fullblocktests package to test consensus
+validation rules.  Mainly provided to avoid dependency cycles internally among
+the different packages in btcd.
+
+## License
+
+Package testhelper is licensed under the [copyfree](http://copyfree.org) ISC
+License.
diff --git a/blockchain/internal/testhelper/common.go b/blockchain/internal/testhelper/common.go
@@ -0,0 +1,31 @@
+package testhelper
+
+import (
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/btcsuite/btcd/wire"
+)
+
+// SpendableOut represents a transaction output that is spendable along with
+// additional metadata such as the block its in and how much it pays.
+type SpendableOut struct {
+	PrevOut wire.OutPoint
+	Amount  btcutil.Amount
+}
+
+// MakeSpendableOutForTx returns a spendable output for the given transaction
+// and transaction output index within the transaction.
+func MakeSpendableOutForTx(tx *wire.MsgTx, txOutIndex uint32) SpendableOut {
+	return SpendableOut{
+		PrevOut: wire.OutPoint{
+			Hash:  tx.TxHash(),
+			Index: txOutIndex,
+		},
+		Amount: btcutil.Amount(tx.TxOut[txOutIndex].Value),
+	}
+}
+
+// MakeSpendableOut returns a spendable output for the given block, transaction
+// index within the block, and transaction output index within the transaction.
+func MakeSpendableOut(block *wire.MsgBlock, txIndex, txOutIndex uint32) SpendableOut {
+	return MakeSpendableOutForTx(block.Transactions[txIndex], txOutIndex)
+}