From f4cdf684312b39673a9ac4a7efc108b24a4b5c8e Mon Sep 17 00:00:00 2001
From: fluency03 <fluency.03@gmail.com>
Date: Tue, 1 May 2018 15:58:42 +0200
Subject: [PATCH] add removeBlock on Blockchain

---
 .../fluency03/blockchain/api/actors/BlockchainActor.scala    | 2 ++
 .../scala/com/fluency03/blockchain/core/Blockchain.scala     | 5 ++++-
 .../scala/com/fluency03/blockchain/core/BlockchainTest.scala | 1 +
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/main/scala/com/fluency03/blockchain/api/actors/BlockchainActor.scala b/src/main/scala/com/fluency03/blockchain/api/actors/BlockchainActor.scala
index 3cd5859..34d1d9e 100644
--- a/src/main/scala/com/fluency03/blockchain/api/actors/BlockchainActor.scala
+++ b/src/main/scala/com/fluency03/blockchain/api/actors/BlockchainActor.scala
@@ -90,4 +90,6 @@ class BlockchainActor extends ActorSupport {
   }
 
 
+
+
 }
diff --git a/src/main/scala/com/fluency03/blockchain/core/Blockchain.scala b/src/main/scala/com/fluency03/blockchain/core/Blockchain.scala
index c4426b0..2b4e0ee 100644
--- a/src/main/scala/com/fluency03/blockchain/core/Blockchain.scala
+++ b/src/main/scala/com/fluency03/blockchain/core/Blockchain.scala
@@ -11,7 +11,8 @@ import scala.annotation.tailrec
 /**
  * Blockchain with difficulty and the chain of Blocks.
  * @param difficulty Difficulty of a Blockchain
- * @param chain Chain of Blocks
+ * @param chain Chain of Blocks, the newest Block is on the head of the chain;
+ *              the first genesis Block is on the last of the chain
  */
 case class Blockchain(difficulty: Int = 4, chain: Seq[Block] = Seq(Block.genesisBlock)) {
 
@@ -20,6 +21,8 @@ case class Blockchain(difficulty: Int = 4, chain: Seq[Block] = Seq(Block.genesis
 
   def addBlock(newBlock: Block): Blockchain = Blockchain(difficulty, newBlock +: chain)
 
+  def removeBlock(): Blockchain = Blockchain(difficulty, chain.tail)
+
   def lastBlock(): Option[Block] = chain.headOption
 
   def mineNextBlock(newBlockData: String, transactions: Seq[Transaction]): Block = {
diff --git a/src/test/scala/com/fluency03/blockchain/core/BlockchainTest.scala b/src/test/scala/com/fluency03/blockchain/core/BlockchainTest.scala
index ae43c55..81825a4 100644
--- a/src/test/scala/com/fluency03/blockchain/core/BlockchainTest.scala
+++ b/src/test/scala/com/fluency03/blockchain/core/BlockchainTest.scala
@@ -65,6 +65,7 @@ class BlockchainTest extends FlatSpec with Matchers  {
     blockchainAdded.lastBlock().get shouldEqual expected
     blockchainAdded.isValid shouldEqual true
     blockchainAdded.length shouldEqual 2
+    blockchainAdded.removeBlock() shouldEqual blockchainToAdd
 
     val blockchainAdded2 = blockchainToAdd.addBlock("This is next Block!", Seq(t1, t2))
     val newLastBlock = blockchainAdded2.lastBlock().get