Close subscription in integration test

* This was causing issues in future tests,
   since the subscription was causing blocks
   and transactions to be added to the DB

blockchain_listener/blockchain_listener.go

@@ -31,3 +31,7 @@ func (listener BlockchainListener) notifyObservers(block core.Block) {
 		observer.NotifyBlockAdded(block)
 	}
 }
+
+func (listener BlockchainListener) Stop() {
+	listener.blockchain.StopListening()
+}

blockchain_listener/blockchain_listener_test.go

@@ -54,4 +54,16 @@ var _ = Describe("Blockchain listeners", func() {
 		close(done)
 	}, 1)
 
+	It("stops listening", func(done Done) {
+		observer := fakes.NewFakeBlockchainObserverTwo()
+		blockchain := &fakes.Blockchain{}
+		listener := blockchain_listener.NewBlockchainListener(blockchain, []core.BlockchainObserver{observer})
+		go listener.Start()
+
+		listener.Stop()
+
+		Expect(blockchain.WasToldToStop).To(BeTrue())
+		close(done)
+	}, 1)
+
 })

core/blockchain.go

@@ -3,4 +3,5 @@ package core
 type Blockchain interface {
 	SubscribeToBlocks(blocks chan Block)
 	StartListening()
+	StopListening()
 }

fakes/blockchain.go

@@ -4,6 +4,7 @@ import "github.com/8thlight/vulcanizedb/core"
 
 type Blockchain struct {
 	outputBlocks  chan core.Block
+	WasToldToStop bool
 }
 
 func (blockchain *Blockchain) SubscribeToBlocks(outputBlocks chan core.Block) {
@@ -15,3 +16,7 @@ func (blockchain Blockchain) AddBlock(block core.Block) {
 }
 
 func (*Blockchain) StartListening() {}
+
+func (blockchain *Blockchain) StopListening() {
+	blockchain.WasToldToStop = true
+}

geth/geth_blockchain.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"github.com/8thlight/vulcanizedb/core"
+	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/ethclient"
 	"golang.org/x/net/context"
@@ -13,6 +14,7 @@ type GethBlockchain struct {
 	client              *ethclient.Client
 	readGethHeaders     chan *types.Header
 	outputBlocks        chan core.Block
+	newHeadSubscription ethereum.Subscription
 }
 
 func NewGethBlockchain(ipcPath string) *GethBlockchain {
@@ -29,7 +31,8 @@ func (blockchain *GethBlockchain) SubscribeToBlocks(blocks chan core.Block) {
 	inputHeaders := make(chan *types.Header, 10)
 	myContext := context.Background()
 	blockchain.readGethHeaders = inputHeaders
-	blockchain.client.SubscribeNewHead(myContext, inputHeaders)
+	subscription, _ := blockchain.client.SubscribeNewHead(myContext, inputHeaders)
+	blockchain.newHeadSubscription = subscription
 }
 
 func (blockchain *GethBlockchain) StartListening() {
@@ -40,3 +43,7 @@ func (blockchain *GethBlockchain) StartListening() {
 		blockchain.outputBlocks <- block
 	}
 }
+
+func (blockchain *GethBlockchain) StopListening() {
+	blockchain.newHeadSubscription.Unsubscribe()
+}

integration_test/geth_blockchain_test.go

@@ -22,11 +22,21 @@ func RunTimePath() string {
 
 var _ = Describe("Reading from the Geth blockchain", func() {
 
-	It("reads two blocks", func(done Done) {
-		observer := fakes.NewFakeBlockchainObserverTwo()
+	var listener blockchain_listener.BlockchainListener
+	var observer *fakes.BlockchainObserver
+
+	BeforeEach(func() {
+		observer = fakes.NewFakeBlockchainObserverTwo()
 		blockchain := geth.NewGethBlockchain(RunTimePath() + "/test_data_dir/geth.ipc")
 		observers := []core.BlockchainObserver{observer}
-		listener := blockchain_listener.NewBlockchainListener(blockchain, observers)
+		listener = blockchain_listener.NewBlockchainListener(blockchain, observers)
+	})
+
+	AfterEach(func() {
+		listener.Stop()
+	})
+
+	It("reads two blocks", func(done Done) {
 		go listener.Start()
 
 		<-observer.WasNotified