From 423887d3d885f8ee31219583277329fe2cfe70a5 Mon Sep 17 00:00:00 2001
From: nsa <elzeigel@gmail.com>
Date: Tue, 27 Aug 2019 00:32:36 -0400
Subject: [PATCH] chanacceptor: adding tests for the RPCAcceptor

This commit adds the TestRPCMultipleAcceptClients test which asserts
that the RPCAcceptor correctly handles multiple Accept callers.
---
 chanacceptor/acceptor_test.go | 156 ++++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)
 create mode 100644 chanacceptor/acceptor_test.go

diff --git a/chanacceptor/acceptor_test.go b/chanacceptor/acceptor_test.go
new file mode 100644
index 00000000..36c7d6b3
--- /dev/null
+++ b/chanacceptor/acceptor_test.go
@@ -0,0 +1,156 @@
+package chanacceptor
+
+import (
+	"bytes"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/lightningnetwork/lnd/lnrpc"
+
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/lightningnetwork/lnd/lnwire"
+)
+
+func randKey(t *testing.T) *btcec.PublicKey {
+	t.Helper()
+
+	priv, err := btcec.NewPrivateKey(btcec.S256())
+	if err != nil {
+		t.Fatalf("unable to generate new public key")
+	}
+
+	return priv.PubKey()
+}
+
+// requestInfo encapsulates the information sent from the RPCAcceptor to the
+// receiver on the other end of the stream.
+type requestInfo struct {
+	chanReq      *ChannelAcceptRequest
+	responseChan chan lnrpc.ChannelAcceptResponse
+}
+
+var defaultAcceptTimeout = 5 * time.Second
+
+func acceptAndIncrementCtr(rpc ChannelAcceptor, req *ChannelAcceptRequest,
+	ctr *uint32, success chan struct{}) {
+
+	result := rpc.Accept(req)
+	if !result {
+		return
+	}
+
+	val := atomic.AddUint32(ctr, 1)
+	if val == 3 {
+		success <- struct{}{}
+	}
+}
+
+// TestMultipleRPCClients tests that the RPCAcceptor is able to handle multiple
+// callers to its Accept method and respond to them correctly.
+func TestRPCMultipleAcceptClients(t *testing.T) {
+
+	var (
+		node = randKey(t)
+
+		firstOpenReq = &ChannelAcceptRequest{
+			Node: node,
+			OpenChanMsg: &lnwire.OpenChannel{
+				PendingChannelID: [32]byte{0},
+			},
+		}
+
+		secondOpenReq = &ChannelAcceptRequest{
+			Node: node,
+			OpenChanMsg: &lnwire.OpenChannel{
+				PendingChannelID: [32]byte{1},
+			},
+		}
+
+		thirdOpenReq = &ChannelAcceptRequest{
+			Node: node,
+			OpenChanMsg: &lnwire.OpenChannel{
+				PendingChannelID: [32]byte{2},
+			},
+		}
+
+		counter uint32
+	)
+
+	quit := make(chan struct{})
+	defer close(quit)
+
+	// Create channels to handle requests and successes.
+	requests := make(chan *requestInfo)
+	successChan := make(chan struct{})
+	errChan := make(chan struct{}, 4)
+
+	// demultiplexReq is a closure used to abstract the RPCAcceptor's request
+	// and response logic.
+	demultiplexReq := func(req *ChannelAcceptRequest) bool {
+		respChan := make(chan lnrpc.ChannelAcceptResponse, 1)
+
+		newRequest := &requestInfo{
+			chanReq:      req,
+			responseChan: respChan,
+		}
+
+		// Send the newRequest to the requests channel.
+		select {
+		case requests <- newRequest:
+		case <-quit:
+			return false
+		}
+
+		// Receive the response and verify that the PendingChanId matches
+		// the ID found in the ChannelAcceptRequest. If no response has been
+		// received in defaultAcceptTimeout, then return false.
+		select {
+		case resp := <-respChan:
+			pendingID := req.OpenChanMsg.PendingChannelID
+			if !bytes.Equal(pendingID[:], resp.PendingChanId) {
+				errChan <- struct{}{}
+				return false
+			}
+
+			return resp.Accept
+		case <-time.After(defaultAcceptTimeout):
+			errChan <- struct{}{}
+			return false
+		case <-quit:
+			return false
+		}
+	}
+
+	rpcAcceptor := NewRPCAcceptor(demultiplexReq)
+
+	// Now we call the Accept method for each request.
+	go func() {
+		acceptAndIncrementCtr(rpcAcceptor, firstOpenReq, &counter, successChan)
+	}()
+
+	go func() {
+		acceptAndIncrementCtr(rpcAcceptor, secondOpenReq, &counter, successChan)
+	}()
+
+	go func() {
+		acceptAndIncrementCtr(rpcAcceptor, thirdOpenReq, &counter, successChan)
+	}()
+
+	for {
+		select {
+		case newRequest := <-requests:
+			newResponse := lnrpc.ChannelAcceptResponse{
+				Accept:        true,
+				PendingChanId: newRequest.chanReq.OpenChanMsg.PendingChannelID[:],
+			}
+
+			newRequest.responseChan <- newResponse
+		case <-errChan:
+			t.Fatalf("unable to accept ChannelAcceptRequest")
+		case <-successChan:
+			return
+		case <-quit:
+		}
+	}
+}