From d6045a0fd575daca24539a4ce676dfb3d8dbe17f Mon Sep 17 00:00:00 2001
From: Torkel Rogstad <torkel@rogstad.io>
Date: Thu, 26 Aug 2021 15:17:35 +0200
Subject: [PATCH] lntest: avoid global ServeMux

Using the default, global ServeMux prevents the same process from
calling `lntest.NewNetworkHarness` multiple times, because we get a
panic when registering HTTP routes.

Instead, we use the ServeMux beloning to the fee service struct.
---
 docs/release-notes/release-notes-0.13.1.md |  4 ++++
 lntest/fee_service.go                      | 10 ++++++----
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/docs/release-notes/release-notes-0.13.1.md b/docs/release-notes/release-notes-0.13.1.md
index 76da2aea..a9c3334b 100644
--- a/docs/release-notes/release-notes-0.13.1.md
+++ b/docs/release-notes/release-notes-0.13.1.md
@@ -42,6 +42,10 @@ tag](https://github.com/lightningnetwork/lnd/pull/5335). A new flag
 test](https://github.com/lightningnetwork/lnd/pull/5348) that would cause the
 test to assert the wrong balance (the miner fee wasn't accounted for).
 
+A bug has been [fixed](https://github.com/lightningnetwork/lnd/pull/5674) in 
+the `lntest` package that prevented multiple test harnesses to be created from 
+the same process.
+
 ## Forwarding Optimizations
 
 [Decoding onion blobs is now done in
diff --git a/lntest/fee_service.go b/lntest/fee_service.go
index f8dbac21..bf80fa0d 100644
--- a/lntest/fee_service.go
+++ b/lntest/fee_service.go
@@ -46,11 +46,13 @@ func startFeeService() *feeService {
 	f.Fees = map[uint32]uint32{feeServiceTarget: 50000}
 
 	listenAddr := fmt.Sprintf(":%v", port)
-	f.srv = &http.Server{
-		Addr: listenAddr,
-	}
+	mux := http.NewServeMux()
+	mux.HandleFunc("/fee-estimates.json", f.handleRequest)
 
-	http.HandleFunc("/fee-estimates.json", f.handleRequest)
+	f.srv = &http.Server{
+		Addr:    listenAddr,
+		Handler: mux,
+	}
 
 	f.wg.Add(1)
 	go func() {