itest: fix off-by-one mining tests

This fixes tests that were surfaced as flaky.  Usually these tests had
an off-by-one error when mining blocks while waiting for a
CSV-encumbered output.

lntest/itest/lnd_multi-hop_htlc_local_timeout_test.go

@@ -160,8 +160,11 @@ func testMultiHopHtlcLocalTimeout(net *lntest.NetworkHarness, t *harnessTest,
 	require.NotNil(t.t, htlcTimeout)
 
 	// We'll mine the remaining blocks in order to generate the sweep
-	// transaction of Bob's commitment output.
-	mineBlocks(t, net, defaultCSV, expectedTxes)
+	// transaction of Bob's commitment output. The commitment was just
+	// mined at the current tip and the sweep will be broadcast so it can
+	// be mined at the tip+defaultCSV'th block, so mine one less to be able
+	// to make mempool assertions.
+	mineBlocks(t, net, defaultCSV-1, expectedTxes)
 
 	// Check that the sweep spends from the mined commitment.
 	txes, err = getNTxsFromMempool(net.Miner.Node, 1, minerMempoolTimeout)
@@ -181,10 +184,15 @@ func testMultiHopHtlcLocalTimeout(net *lntest.NetworkHarness, t *harnessTest,
 	require.NotZero(t.t, forceCloseChan.LimboBalance)
 	require.NotZero(t.t, len(forceCloseChan.PendingHtlcs))
 
-	// Now we'll mine an additional block, which should confirm Bob's commit
-	// sweep. This block should also prompt Bob to broadcast their second
+	// Mine a block to confirm Bob's commit sweep tx and assert it was in
+	// fact mined.
+	block := mineBlocks(t, net, 1, 1)[0]
+	commitSweepTxid := txes[0].TxHash()
+	assertTxInBlock(t, block, &commitSweepTxid)
+
+	// Mine an additional block to prompt Bob to broadcast their second
 	// layer sweep due to the CSV on the HTLC timeout output.
-	mineBlocks(t, net, 1, 1)
+	mineBlocks(t, net, 1, 0)
 	assertSpendingTxInMempool(
 		t, net.Miner.Node, minerMempoolTimeout, wire.OutPoint{
 			Hash:  *htlcTimeout,

lntest/itest/lnd_multi-hop_htlc_remote_chain_claim_test.go

@@ -97,19 +97,28 @@ func testMultiHopHtlcRemoteChainClaim(net *lntest.NetworkHarness, t *harnessTest
 	err = waitForChannelPendingForceClose(ctxt, alice, aliceChanPoint)
 	require.NoError(t.t, err)
 
+	// After closeChannelAndAssertType returns, it has mined a block so now
+	// bob will attempt to redeem his anchor commitment (if the channel
+	// type is of that type).
+	if c == commitTypeAnchors {
+		_, err = waitForNTxsInMempool(net.Miner.Node, 1, minerMempoolTimeout)
+		if err != nil {
+			t.Fatalf("unable to find bob's anchor commit sweep: %v", err)
+
+		}
+	}
+
 	// Mine enough blocks for Alice to sweep her funds from the force
-	// closed channel.
-	_, err = net.Miner.Node.Generate(defaultCSV)
+	// closed channel. closeCHannelAndAssertType() already mined a block
+	// containing the commitment tx and the commit sweep tx will be
+	// broadcast immediately before it can be included in a block, so mine
+	// one less than defaultCSV in order to perform mempool assertions.
+	_, err = net.Miner.Node.Generate(defaultCSV - 1)
 	require.NoError(t.t, err)
 
-	// Alice should now sweep her funds. If there are anchors, Alice should
-	// also sweep hers.
-	expectedTxes := 1
-	if c == commitTypeAnchors {
-		expectedTxes = 2
-	}
+	// Alice should now sweep her funds.
 	_, err = waitForNTxsInMempool(
-		net.Miner.Node, expectedTxes, minerMempoolTimeout,
+		net.Miner.Node, 1, minerMempoolTimeout,
 	)
 	require.NoError(t.t, err)
 
@@ -138,8 +147,13 @@ func testMultiHopHtlcRemoteChainClaim(net *lntest.NetworkHarness, t *harnessTest
 	_, err = net.Miner.Node.Generate(numBlocks)
 	require.NoError(t.t, err)
 
-	// Carol's commitment transaction should now be in the mempool. If there
-	// are anchors, Carol also sweeps her anchor.
+	expectedTxes := 1
+	if c == commitTypeAnchors {
+		expectedTxes = 2
+	}
+
+	// Carol's commitment transaction should now be in the mempool. If
+	// there are anchors, Carol also sweeps her anchor.
 	_, err = waitForNTxsInMempool(
 		net.Miner.Node, expectedTxes, minerMempoolTimeout,
 	)

lntest/itest/lnd_multi-hop_local_force_close_on_chain_htlc_timeout_test.go

@@ -100,7 +100,11 @@ func testMultiHopLocalForceCloseOnChainHtlcTimeout(net *lntest.NetworkHarness,
 		require.NoError(t.t, err)
 	}
 
-	_, err = net.Miner.Node.Generate(defaultCSV)
+	// The sweep is broadcast on the block immediately before the CSV
+	// expires and the commitment was already mined inside
+	// closeChannelAndAssertType(), so mine one block less than defaultCSV
+	// in order to perform mempool assertions.
+	_, err = net.Miner.Node.Generate(defaultCSV - 1)
 	require.NoError(t.t, err)
 
 	_, err = waitForTxInMempool(net.Miner.Node, minerMempoolTimeout)
@@ -108,7 +112,7 @@ func testMultiHopLocalForceCloseOnChainHtlcTimeout(net *lntest.NetworkHarness,
 
 	// We'll now mine enough blocks for the HTLC to expire. After this, Bob
 	// should hand off the now expired HTLC output to the utxo nursery.
-	numBlocks := padCLTV(uint32(finalCltvDelta - defaultCSV - 1))
+	numBlocks := padCLTV(uint32(finalCltvDelta - defaultCSV))
 	_, err = net.Miner.Node.Generate(numBlocks)
 	require.NoError(t.t, err)
 

lntest/itest/lnd_test.go

@@ -409,7 +409,10 @@ func cleanupForceClose(t *harnessTest, net *lntest.NetworkHarness,
 
 	// Mine enough blocks for the node to sweep its funds from the force
 	// closed channel.
-	_, err = net.Miner.Node.Generate(defaultCSV)
+	//
+	// The commit sweep resolver is able to broadcast the sweep tx up to
+	// one block before the CSV elapses, so wait until defaulCSV-1.
+	_, err = net.Miner.Node.Generate(defaultCSV - 1)
 	if err != nil {
 		t.Fatalf("unable to generate blocks: %v", err)
 	}
@@ -7726,7 +7729,7 @@ func testFailingChannel(net *lntest.NetworkHarness, t *harnessTest) {
 
 	// Mine enough blocks for Alice to sweep her funds from the force
 	// closed channel.
-	_, err = net.Miner.Node.Generate(defaultCSV)
+	_, err = net.Miner.Node.Generate(defaultCSV - 1)
 	if err != nil {
 		t.Fatalf("unable to generate blocks: %v", err)
 	}
@@ -9505,7 +9508,11 @@ func assertDLPExecuted(net *lntest.NetworkHarness, t *harnessTest,
 	}
 
 	// After the Carol's output matures, she should also reclaim her funds.
-	mineBlocks(t, net, defaultCSV-1, 0)
+	//
+	// The commit sweep resolver publishes the sweep tx at defaultCSV-1 and
+	// we already mined one block after the commitmment was published, so
+	// take that into account.
+	mineBlocks(t, net, defaultCSV-1-1, 0)
 	carolSweep, err := waitForTxInMempool(
 		net.Miner.Node, minerMempoolTimeout,
 	)
@@ -9796,7 +9803,7 @@ func testDataLossProtection(net *lntest.NetworkHarness, t *harnessTest) {
 	}
 
 	// Mine enough blocks for Carol to sweep her funds.
-	mineBlocks(t, net, defaultCSV, 0)
+	mineBlocks(t, net, defaultCSV-1, 0)
 
 	carolSweep, err := waitForTxInMempool(net.Miner.Node, minerMempoolTimeout)
 	if err != nil {