From d87fd6138d12473caa2b980a8a1df2ab48d24009 Mon Sep 17 00:00:00 2001
From: Elle Mouton <elle.mouton@gmail.com>
Date: Tue, 19 Mar 2024 13:17:20 +0200
Subject: [PATCH] itest: mine blocks on tower session assertion failure

In the tower session itest, we make sure to mine blocks on session count
assertion failure. This required because the session count is expected
to change only when 2 things both happen: 1) a closable session is
queued and 2) a new block notification comes through _after_ the session
has been queued. Only then will it be deleted. So we need to do this to
prevent the case where all the block notifications are consumed _before_
the session is queued for deletion. This flake tended to happen in the
windows itest.
---
 itest/lnd_watchtower_test.go | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/itest/lnd_watchtower_test.go b/itest/lnd_watchtower_test.go
index bfd1425a5..6459ac0b1 100644
--- a/itest/lnd_watchtower_test.go
+++ b/itest/lnd_watchtower_test.go
@@ -65,7 +65,9 @@ func testTowerClientTowerAndSessionManagement(ht *lntest.HarnessTest) {
 	}
 	dave.RPC.AddTower(addWallisReq)
 
-	assertNumSessions := func(towerPk []byte, expectedNum int) {
+	assertNumSessions := func(towerPk []byte, expectedNum int,
+		mineOnFail bool) {
+
 		err := wait.NoError(func() error {
 			info := dave.RPC.GetTowerInfo(
 				&wtclientrpc.GetTowerInfoRequest{
@@ -82,6 +84,10 @@ func testTowerClientTowerAndSessionManagement(ht *lntest.HarnessTest) {
 				return nil
 			}
 
+			if mineOnFail {
+				ht.Miner.MineBlocksSlow(1)
+			}
+
 			return fmt.Errorf("expected %d sessions, got %d",
 				expectedNum, numSessions)
 		}, defaultTimeout)
@@ -91,7 +97,7 @@ func testTowerClientTowerAndSessionManagement(ht *lntest.HarnessTest) {
 	// Assert that there are a few sessions between Dave and Wallis. There
 	// should be one per client. There are currently 3 types of clients, so
 	// we expect 3 sessions.
-	assertNumSessions(wallisPk, 3)
+	assertNumSessions(wallisPk, 3, false)
 
 	// Before we make a channel, we'll load up Dave with some coins sent
 	// directly from the miner.
@@ -145,7 +151,7 @@ func testTowerClientTowerAndSessionManagement(ht *lntest.HarnessTest) {
 		Pubkey:  wilmaPk,
 		Address: wilmaListener,
 	})
-	assertNumSessions(wilmaPk, 3)
+	assertNumSessions(wilmaPk, 3, false)
 
 	// The updates from before should now appear on the new watchtower.
 	assertNumBackups(ht, dave.RPC, wilmaPk, 4, false)
@@ -163,7 +169,7 @@ func testTowerClientTowerAndSessionManagement(ht *lntest.HarnessTest) {
 	// number of sessions with Wallis has not changed - in other words, the
 	// previously used session was re-used.
 	assertNumBackups(ht, dave.RPC, wallisPk, 8, false)
-	assertNumSessions(wallisPk, 3)
+	assertNumSessions(wallisPk, 3, false)
 
 	findSession := func(towerPk []byte, numBackups uint32) []byte {
 		info := dave.RPC.GetTowerInfo(&wtclientrpc.GetTowerInfoRequest{
@@ -196,7 +202,7 @@ func testTowerClientTowerAndSessionManagement(ht *lntest.HarnessTest) {
 	// This should force the client to negotiate a new session. The old
 	// session still remains in our session list since the channel for which
 	// it has updates for is still open.
-	assertNumSessions(wallisPk, 4)
+	assertNumSessions(wallisPk, 4, false)
 
 	// Any new back-ups should now be backed up on a different session.
 	generateBackups(ht, dave, ht.Alice, 2)
@@ -212,8 +218,12 @@ func testTowerClientTowerAndSessionManagement(ht *lntest.HarnessTest) {
 	// The session that was previously terminated now gets deleted since
 	// the channel for which it has updates has now been closed. All the
 	// remaining sessions are not yet closable since they are not yet
-	// exhausted and are all still active.
-	assertNumSessions(wallisPk, 3)
+	// exhausted and are all still active. We set mineOnFail to true here
+	// so that we can ensure that the closable session queue continues to
+	// be checked on each new block. It could have been the case that all
+	// checks with the above mined blocks were completed before the
+	// closable session was queued.
+	assertNumSessions(wallisPk, 3, true)
 
 	// For the sake of completion, we call RemoveTower here for both towers
 	// to show that this should never error.