diff --git a/.travis.yml b/.travis.yml
index 120c9a6a6..6cefeb9fe 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,12 +1,13 @@
 language: go
 go:
 - master
-install: |
-  export GOPATH=$HOME/gopath
-  mkdir -p $HOME/gopath/src/harmony-benchmark
-  rsync -az ${TRAVIS_BUILD_DIR}/ $HOME/gopath/src/harmony-benchmark/
-  export TRAVIS_BUILD_DIR=$HOME/gopath/src/harmony-benchmark
-  cd $HOME/gopath/src/harmony-benchmark
+install:
+  - export GOPATH=$HOME/gopath
+  - mkdir -p $HOME/gopath/src/harmony-benchmark
+  - rsync -az ${TRAVIS_BUILD_DIR}/ $HOME/gopath/src/harmony-benchmark/
+  - export TRAVIS_BUILD_DIR=$HOME/gopath/src/harmony-benchmark
+  - cd $HOME/gopath/src/harmony-benchmark
+  - go build
 notifications:
   slack:
     secure: 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
diff --git a/blockchain/utxopool.go b/blockchain/utxopool.go
index 036585059..cac48da40 100644
--- a/blockchain/utxopool.go
+++ b/blockchain/utxopool.go
@@ -5,6 +5,7 @@ import (
 )
 
 const (
+	// MaxNumberOfTransactions is the max number of transaction per a block.
 	MaxNumberOfTransactions = 100
 )
 
@@ -16,9 +17,9 @@ type UTXOPool struct {
 }
 
 // VerifyTransactions verifies if a list of transactions valid.
-func (utxopool *UTXOPool) VerifyTransactions(transactions []*Transaction) bool {
+func (utxoPool *UTXOPool) VerifyTransactions(transactions []*Transaction) bool {
 	spentTXOs := make(map[string]map[string]map[int]bool)
-	if utxopool != nil {
+	if utxoPool != nil {
 		for _, tx := range transactions {
 			inTotal := 0
 			// Calculate the sum of TxInput
@@ -41,7 +42,7 @@ func (utxopool *UTXOPool) VerifyTransactions(transactions []*Transaction) bool {
 				spentTXOs[in.Address][inTxID][index] = true
 
 				// Sum the balance up to the inTotal.
-				if val, ok := utxopool.utxo[in.Address][inTxID][index]; ok {
+				if val, ok := utxoPool.utxo[in.Address][inTxID][index]; ok {
 					inTotal += val
 				} else {
 					return false
@@ -61,111 +62,114 @@ func (utxopool *UTXOPool) VerifyTransactions(transactions []*Transaction) bool {
 	return true
 }
 
-// VerifyOneTransactionAndUpdate verifies if a list of transactions valid.
-func (utxopool *UTXOPool) VerifyOneTransaction(tx *Transaction) bool {
-    spentTXOs := make(map[string]map[string]map[int]bool)
-    txID := hex.EncodeToString(tx.ID)
-    inTotal := 0
-    // Calculate the sum of TxInput
-    for _, in := range tx.TxInput {
-        inTxID := hex.EncodeToString(in.TxID)
-        index := in.TxOutputIndex
-        // Check if the transaction with the addres is spent or not.
-        if val, ok := utxopool.utxo[in.Address][inTxID][index]; ok {
-            if spentTXOs[in.Address][inTxID][index] {
-                return false
-            }
-            inTotal += val
-        } else {
-            return false
-        }
-        // Mark the transactions with the address and index spent.
-        if _, ok := spentTXOs[in.Address]; !ok {
-            spentTXOs[in.Address] = make(map[string]map[int]bool)
-        }
-        if _, ok := spentTXOs[in.Address][inTxID]; !ok {
-            spentTXOs[in.Address][inTxID] = make(map[int]bool)
-        }
-        spentTXOs[in.Address][inTxID][index] = true
-    }
-
-    outTotal := 0
-    // Calculate the sum of TxOutput
-    for index, out := range tx.TxOutput {
-        if val, ok := spentTXOs[out.Address][txID][index]; ok {
-            return false
-        }
-        outTotal += out.Value
-    }
-    if inTotal != outTotal {
-        return false
-    }
+// VerifyOneTransaction verifies if a list of transactions valid.
+func (utxoPool *UTXOPool) VerifyOneTransaction(tx *Transaction) bool {
+	spentTXOs := make(map[string]map[string]map[int]bool)
+	txID := hex.EncodeToString(tx.ID)
+	inTotal := 0
+	// Calculate the sum of TxInput
+	for _, in := range tx.TxInput {
+		inTxID := hex.EncodeToString(in.TxID)
+		index := in.TxOutputIndex
+		// Check if the transaction with the addres is spent or not.
+		if val, ok := utxoPool.utxo[in.Address][inTxID][index]; ok {
+			if spentTXOs[in.Address][inTxID][index] {
+				return false
+			}
+			inTotal += val
+		} else {
+			return false
+		}
+		// Mark the transactions with the address and index spent.
+		if _, ok := spentTXOs[in.Address]; !ok {
+			spentTXOs[in.Address] = make(map[string]map[int]bool)
+		}
+		if _, ok := spentTXOs[in.Address][inTxID]; !ok {
+			spentTXOs[in.Address][inTxID] = make(map[int]bool)
+		}
+		spentTXOs[in.Address][inTxID][index] = true
+	}
+
+	outTotal := 0
+	// Calculate the sum of TxOutput
+	for index, out := range tx.TxOutput {
+		if _, ok := spentTXOs[out.Address][txID][index]; ok {
+			return false
+		}
+		outTotal += out.Value
+	}
+	if inTotal != outTotal {
+		return false
+	}
 	return true
 }
 
-func (utxopool *UTXOPool) Update(tx* Transaction) {
-	if utxopool != nil {
-        txID := hex.EncodeToString(tx.ID)
-
-        // Remove
-        for _, in := range tx.TxInput {
-            inTxID := hex.EncodeToString(in.TxID)
-            delete(utxopool.utxo[in.Address][inTxID], in.TxOutputIndex)
-        }
-
-        // Update
-        for index, out := range tx.TxOutput {
-            if _, ok := utxopool.utxo[out.Address]; !ok {
-                utxopool.utxo[out.Address] = make(map[string]map[int]int)
-                utxopool.utxo[out.Address][txID] = make(map[int]int)
-            }
-            if _, ok := utxopool.utxo[out.Address][txID]; !ok {
-                utxopool.utxo[out.Address][txID] = make(map[int]int)
-            }
-            utxopool.utxo[out.Address][txID][index] = out.Value
-        }
-    }
+// UpdateOneTransaction updates utxoPool in respect to the new Transaction.
+func (utxoPool *UTXOPool) UpdateOneTransaction(tx *Transaction) {
+	if utxoPool != nil {
+		txID := hex.EncodeToString(tx.ID)
+
+		// Remove
+		for _, in := range tx.TxInput {
+			inTxID := hex.EncodeToString(in.TxID)
+			delete(utxoPool.utxo[in.Address][inTxID], in.TxOutputIndex)
+		}
+
+		// Update
+		for index, out := range tx.TxOutput {
+			if _, ok := utxoPool.utxo[out.Address]; !ok {
+				utxoPool.utxo[out.Address] = make(map[string]map[int]int)
+				utxoPool.utxo[out.Address][txID] = make(map[int]int)
+			}
+			if _, ok := utxoPool.utxo[out.Address][txID]; !ok {
+				utxoPool.utxo[out.Address][txID] = make(map[int]int)
+			}
+			utxoPool.utxo[out.Address][txID][index] = out.Value
+		}
+	}
 }
 
-func (utxopool *UTXOPool) VerifyOneTransactionAndUpdate(tx *Transaction) bool {
-    if utxopool.VerifyOneTransaction(tx) {
-        utxopool.Update(tx)
-        return true
-    }
-    return false
+// VerifyOneTransactionAndUpdate verifies and update a valid transaction.
+// Return false if the transaction is not valid.
+func (utxoPool *UTXOPool) VerifyOneTransactionAndUpdate(tx *Transaction) bool {
+	if utxoPool.VerifyOneTransaction(tx) {
+		utxoPool.UpdateOneTransaction(tx)
+		return true
+	}
+	return false
 }
 
 // VerifyAndUpdate verifies a list of transactions and update utxoPool.
-func (utxopool *UTXOPool) VerifyAndUpdate(transactions []*Transaction) bool {
-	if utxopool.VerifyTransactions(transactions) {
-		utxopool.Update(transactions)
+func (utxoPool *UTXOPool) VerifyAndUpdate(transactions []*Transaction) bool {
+	if utxoPool.VerifyTransactions(transactions) {
+		utxoPool.Update(transactions)
 		return true
 	}
 	return false
 }
 
 // Update utxo balances with a list of new transactions.
-func (utxopool *UTXOPool) Update(transactions []*Transaction) {
-	if utxopool != nil {
+func (utxoPool *UTXOPool) Update(transactions []*Transaction) {
+	if utxoPool != nil {
 		for _, tx := range transactions {
 			curTxID := hex.EncodeToString(tx.ID)
 
 			// Remove
 			for _, in := range tx.TxInput {
 				inTxID := hex.EncodeToString(in.TxID)
-				delete(utxopool.utxo[in.Address][inTxID], in.TxOutputIndex)
+				delete(utxoPool.utxo[in.Address][inTxID], in.TxOutputIndex)
 			}
 
 			// Update
 			for index, out := range tx.TxOutput {
-				if _, ok := utxopool.utxo[out.Address]; !ok {
-					utxopool.utxo[out.Address] = make(map[string]map[int]int)
-					utxopool.utxo[out.Address][curTxID] = make(map[int]int)
+				if _, ok := utxoPool.utxo[out.Address]; !ok {
+					utxoPool.utxo[out.Address] = make(map[string]map[int]int)
+					utxoPool.utxo[out.Address][curTxID] = make(map[int]int)
 				}
-				if _, ok := utxopool.utxo[out.Address][curTxID]; !ok {
-					utxopool.utxo[out.Address][curTxID] = make(map[int]int)
+				if _, ok := utxoPool.utxo[out.Address][curTxID]; !ok {
+					utxoPool.utxo[out.Address][curTxID] = make(map[int]int)
 				}
-				utxopool.utxo[out.Address][curTxID][index] = out.Value
+				utxoPool.utxo[out.Address][curTxID][index] = out.Value
 			}
 		}
 	}
@@ -191,13 +195,14 @@ func CreateUTXOPoolFromGenesisBlockChain(bc *Blockchain) *UTXOPool {
 }
 
 // SelectTransactionsForNewBlock returns a list of index of valid transactions for the new block.
-func (utxoPool *UTXOPool) SelectTransactionsForNewBlock(transactions []*Transaction) (selected, unselected []*Transaction) {
-	selected, unselected = []*Transaction{}, []*Transaction{}
-	for id, tx := range transactions {
-        if len(selected) < MaxNumberOfTransactions && utxoPool.VerifyOneTransactionAndUpdate(tx) {
-            append(selected, tx)
-        } else {
-            append(unselected, tx)
-        }
+func (utxoPool *UTXOPool) SelectTransactionsForNewBlock(transactions []*Transaction) ([]*Transaction, []*Transaction) {
+	selected, unselected := []*Transaction{}, []*Transaction{}
+	for _, tx := range transactions {
+		if len(selected) < MaxNumberOfTransactions && utxoPool.VerifyOneTransactionAndUpdate(tx) {
+			selected = append(selected, tx)
+		} else {
+			unselected = append(unselected, tx)
+		}
 	}
+	return selected, unselected
 }
diff --git a/blockchain/utxopool_test.go b/blockchain/utxopool_test.go
index 4e76f322e..c47fb4b24 100644
--- a/blockchain/utxopool_test.go
+++ b/blockchain/utxopool_test.go
@@ -4,8 +4,20 @@ import (
 	"testing"
 )
 
-func TestVerifyTransactions(t *testing.T) {
-	if cbtx := NewCoinbaseTX("minh", genesisCoinbaseData); cbtx == nil {
-		t.Errorf("failed to create a coinbase transaction.")
+func TestVerifyOneTransactionAndUpdate(t *testing.T) {
+	bc := CreateBlockchain("minh")
+	utxoPool := CreateUTXOPoolFromGenesisBlockChain(bc)
+
+	bc.AddNewUserTransfer(utxoPool, "minh", "alok", 3)
+	bc.AddNewUserTransfer(utxoPool, "minh", "rj", 100)
+
+	tx := bc.NewUTXOTransaction("minh", "mark", 10)
+	if tx == nil {
+		t.Error("failed to create a new transaction.")
 	}
+
+	// if utxoPool.VerifyOneTransaction(tx) {
+	// 	t.Error("failed to verify a valid transaction.")
+	// }
+
 }