From 49b18b4d353b74578aba08fef5b59c4cbc0e5c6e Mon Sep 17 00:00:00 2001 From: Olaoluwa Osuntokun Date: Tue, 6 Jul 2021 16:35:04 -0700 Subject: [PATCH] lnwallet: add test case to exercise MayAddOutgoingHtlc bug As is, if the remote party proposes a min HTLC of 0 `mSat` to us, then we won't ever be able to _send outgoing_ in the channel as the `MayAddOutgoingHtlc` will attempt to add a zero-value HTLC, which isn't allowed within the protocol. The default channels created actually already use a min HTLC value of zero within the tests, so this test case fails as is. --- lnwallet/channel_test.go | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/lnwallet/channel_test.go b/lnwallet/channel_test.go index 6de8b2ac..6f190ade 100644 --- a/lnwallet/channel_test.go +++ b/lnwallet/channel_test.go @@ -9648,3 +9648,24 @@ func TestChannelSignedAckRegression(t *testing.T) { err = aliceChannel.ReceiveNewCommitment(bobSig, bobHtlcSigs) require.NoError(t, err) } + +// TestMayAddOutgoingHtlcZeroValue tests that if the minHTLC value of the +// channel is zero, then the MayAddOutgoingHtlc doesn't exit early due to +// running into a zero valued HTLC. +func TestMayAddOutgoingHtlcZeroValue(t *testing.T) { + t.Parallel() + + // The default channel created as a part of the test fixture already + // has a MinHTLC value of zero, so we don't need to do anything here + // other than create it. + aliceChannel, bobChannel, cleanUp, err := CreateTestChannels( + channeldb.SingleFunderTweaklessBit, + ) + require.NoError(t, err) + defer cleanUp() + + // The channels start out with a 50/50 balance, so both sides should be + // able to add an outgoing HTLC. + require.NoError(t, aliceChannel.MayAddOutgoingHtlc()) + require.NoError(t, bobChannel.MayAddOutgoingHtlc()) +}