itest+lntest: harden sweep and watchtower flakes

itest/lnd_revocation_test.go

@@ -279,8 +279,10 @@ func revokedCloseRetributionZeroValueRemoteOutputCase(ht *lntest.HarnessTest,
 	// backup.
 	ht.EnsureConnected(dave, carol)
 
-	// Once connected, give Dave some time to enable the channel again.
+	// Once connected, wait for both channel links to be active again.
 	ht.AssertChannelInGraph(dave, chanPoint)
+	ht.AssertChannelActive(dave, chanPoint)
+	ht.AssertChannelActive(carol, chanPoint)
 
 	// Finally, send payments from Dave to Carol, consuming Carol's
 	// remaining payment hashes.
@@ -507,8 +509,10 @@ func revokedCloseRetributionRemoteHodlCase(ht *lntest.HarnessTest,
 	// backup.
 	ht.EnsureConnected(dave, carol)
 
-	// Once connected, give Dave some time to enable the channel again.
+	// Once connected, wait for both channel links to be active again.
 	ht.AssertChannelInGraph(dave, chanPoint)
+	ht.AssertChannelActive(dave, chanPoint)
+	ht.AssertChannelActive(carol, chanPoint)
 
 	// Finally, send payments from Dave to Carol, consuming Carol's
 	// remaining payment hashes.

itest/lnd_watchtower_test.go

@@ -448,8 +448,10 @@ func testRevokedCloseRetributionAltruistWatchtowerCase(ht *lntest.HarnessTest,
 	// backup.
 	ht.EnsureConnected(dave, carol)
 
-	// Once connected, give Dave some time to enable the channel again.
+	// Once connected, wait for both channel links to be active again.
 	ht.AssertChannelInGraph(dave, chanPoint)
+	ht.AssertChannelActive(dave, chanPoint)
+	ht.AssertChannelActive(carol, chanPoint)
 
 	// Finally, send payments from Dave to Carol, consuming Carol's
 	// remaining payment hashes.

lntest/miner/miner.go

@@ -589,13 +589,29 @@ func (h *HarnessMiner) AssertOutpointInMempool(op wire.OutPoint) *wire.MsgTx {
 // GetNumTxsFromMempool polls until finding the desired number of transactions
 // in the miner's mempool and returns the full transactions to the caller.
 func (h *HarnessMiner) GetNumTxsFromMempool(n int) []*wire.MsgTx {
-	txids := h.AssertNumTxsInMempool(n)
-
 	var txes []*wire.MsgTx
-	for _, txid := range txids {
-		tx := h.GetRawTransaction(txid)
-		txes = append(txes, tx.MsgTx())
-	}
+
+	err := wait.NoError(func() error {
+		txids := h.AssertNumTxsInMempool(n)
+
+		txes = nil
+		for _, txid := range txids {
+			// The mempool can change between listing its txids
+			// and fetching a transaction. For example, sweep
+			// tests may RBF-replace a tx while we iterate over
+			// the snapshot. Retry with a fresh snapshot when
+			// that happens.
+			tx, err := h.backend.GetRawTransaction(&txid)
+			if err != nil {
+				return err
+			}
+
+			txes = append(txes, tx.MsgTx())
+		}
+
+		return nil
+	}, wait.MinerMempoolTimeout)
+	require.NoError(h, err, "get txs from mempool")
 
 	return txes
 }