From a8e513fd0ca4c482e8adf52ed53b50151844a40f Mon Sep 17 00:00:00 2001
From: Chris Stewart <stewart.chris1234@gmail.com>
Date: Mon, 10 Dec 2018 10:53:45 -0500
Subject: [PATCH] Rework TransactionWitness, add more tests for resizing (#267)

Turn down logging again
---
 .../transaction/TransactionWitnessSpec.scala  | 29 +++++++++++++++++--
 .../transaction/TransactionWitness.scala      | 16 +++++-----
 2 files changed, 33 insertions(+), 12 deletions(-)

diff --git a/core-test/src/test/scala/org/bitcoins/core/protocol/transaction/TransactionWitnessSpec.scala b/core-test/src/test/scala/org/bitcoins/core/protocol/transaction/TransactionWitnessSpec.scala
index df87f602a2..bf9f94abcd 100644
--- a/core-test/src/test/scala/org/bitcoins/core/protocol/transaction/TransactionWitnessSpec.scala
+++ b/core-test/src/test/scala/org/bitcoins/core/protocol/transaction/TransactionWitnessSpec.scala
@@ -1,16 +1,39 @@
 package org.bitcoins.core.protocol.transaction
 
+import org.bitcoins.core.crypto.{ECPrivateKey, EmptyDigitalSignature}
 import org.bitcoins.core.gen.WitnessGenerators
-import org.scalacheck.{Prop, Properties}
+import org.bitcoins.core.protocol.script._
+import org.scalacheck.Prop
+import org.scalatest.{FlatSpec, MustMatchers}
 
 /**
   * Created by chris on 11/28/16.
   */
-class TransactionWitnessSpec extends Properties("TransactionWitnessSpec") {
+class TransactionWitnessSpec extends FlatSpec with MustMatchers {
 
-  property("serialization symmetry") = {
+  behavior of "TransactionWitness"
+
+  it must "have serialization symmetry" in {
     Prop.forAll(WitnessGenerators.transactionWitness) { witness =>
       TransactionWitness(witness.hex, witness.witnesses.size) == witness
     }
   }
+
+  it must "be able to resize a witness to the given index" in {
+    val empty = EmptyWitness
+    val pubKey = ECPrivateKey.freshPrivateKey.publicKey
+    val p2pkh = P2PKHScriptSignature(EmptyDigitalSignature,pubKey)
+    val scriptWit = P2WPKHWitnessV0.fromP2PKHScriptSig(p2pkh)
+    val updated = empty.updated(2,scriptWit)
+
+    updated.witnesses.length must be (3)
+  }
+
+
+  it must "fail to update a negative index witness" in {
+    intercept[IndexOutOfBoundsException] {
+      EmptyWitness.updated(-1,EmptyScriptWitness)
+    }
+  }
+
 }
diff --git a/core/src/main/scala/org/bitcoins/core/protocol/transaction/TransactionWitness.scala b/core/src/main/scala/org/bitcoins/core/protocol/transaction/TransactionWitness.scala
index 27613b188b..81f73527e0 100644
--- a/core/src/main/scala/org/bitcoins/core/protocol/transaction/TransactionWitness.scala
+++ b/core/src/main/scala/org/bitcoins/core/protocol/transaction/TransactionWitness.scala
@@ -12,24 +12,23 @@ import scodec.bits.ByteVector
   * [[https://github.com/bitcoin/bitcoin/blob/b4e4ba475a5679e09f279aaf2a83dcf93c632bdb/src/primitives/transaction.h#L232-L268]]
   */
 sealed abstract class TransactionWitness extends NetworkElement {
-  def witnesses: Vector[ScriptWitness]
+  val witnesses: Vector[ScriptWitness]
 
-  override def bytes = RawTransactionWitnessParser.write(this)
+  override def bytes: ByteVector = {
+    RawTransactionWitnessParser.write(this)
+  }
 
   /**
     * Update the [[witnesses]] index to the given witness
     * Pads the witnesses vector if needed to accomodate the new witness
     */
   def updated(index: Int, witness: ScriptWitness): TransactionWitness = {
-    val scriptWits = {
+    val scriptWits: Vector[ScriptWitness] = {
       if (index < 0) {
         throw new IndexOutOfBoundsException(index.toString)
       } else if (index >= witnesses.size) {
-
         val padded = padScriptWitness(index)
-
         padded.updated(index, witness)
-
       } else {
         witnesses.updated(index, witness)
       }
@@ -58,9 +57,8 @@ sealed abstract class TransactionWitness extends NetworkElement {
 
 /** Used to represent a transaction witness pre segwit, see BIP141 for details */
 case object EmptyWitness extends TransactionWitness {
-  override def bytes = ByteVector.low(1)
-  override def witnesses: Vector[ScriptWitness] = Vector.empty
-
+  override val bytes: ByteVector = ByteVector.low(1)
+  override val witnesses: Vector[ScriptWitness] = Vector.empty
 }
 
 object TransactionWitness {