lntest: make sure chain backend is synced to miner

We sometimes see `timeout waiting for UTXOs` error from bitcoind-related
itests due to the chain backend not synced to the miner. We now assert
it's synced before continue.

lntest/harness.go

@@ -481,6 +481,14 @@ func (h *HarnessTest) NewNode(name string,
 	err = node.Start(h.runCtx)
 	require.NoError(h, err, "failed to start node %s", node.Name())
 
+	// Get the miner's best block hash.
+	bestBlock, err := h.miner.Client.GetBestBlockHash()
+	require.NoError(h, err, "unable to get best block hash")
+
+	// Wait until the node's chain backend is synced to the miner's best
+	// block.
+	h.WaitForBlockchainSyncTo(node, *bestBlock)
+
 	return node
 }
 
@@ -490,12 +498,7 @@ func (h *HarnessTest) NewNode(name string,
 func (h *HarnessTest) NewNodeWithCoins(name string,
 	extraArgs []string) *node.HarnessNode {
 
-	node, err := h.manager.newNode(h.T, name, extraArgs, nil, false)
-	require.NoErrorf(h, err, "unable to create new node for %s", name)
-
-	// Start the node.
-	err = node.Start(h.runCtx)
-	require.NoError(h, err, "failed to start node %s", node.Name())
+	node := h.NewNode(name, extraArgs)
 
 	// Load up the wallets of the node with 5 outputs of 1 BTC each.
 	const (

lntest/harness_assertion.go

@@ -61,9 +61,9 @@ func (h *HarnessTest) WaitForBlockchainSync(hn *node.HarnessNode) {
 
 // WaitForBlockchainSyncTo waits until the node is synced to bestBlock.
 func (h *HarnessTest) WaitForBlockchainSyncTo(hn *node.HarnessNode,
-	bestBlock *wire.MsgBlock) {
+	bestBlock chainhash.Hash) {
 
-	bestBlockHash := bestBlock.BlockHash().String()
+	bestBlockHash := bestBlock.String()
 	err := wait.NoError(func() error {
 		resp := hn.RPC.GetInfo()
 		if resp.SyncedToChain {
@@ -1629,7 +1629,7 @@ func (h *HarnessTest) AssertActiveNodesSynced() {
 
 // AssertActiveNodesSyncedTo asserts all active nodes have synced to the
 // provided bestBlock.
-func (h *HarnessTest) AssertActiveNodesSyncedTo(bestBlock *wire.MsgBlock) {
+func (h *HarnessTest) AssertActiveNodesSyncedTo(bestBlock chainhash.Hash) {
 	for _, node := range h.manager.activeNodes {
 		h.WaitForBlockchainSyncTo(node, bestBlock)
 	}

lntest/harness_miner.go

@@ -41,7 +41,7 @@ func (h *HarnessTest) MineBlocks(num int) {
 		// Check the block doesn't have any txns except the coinbase.
 		if len(block.Transactions) <= 1 {
 			// Make sure all the active nodes are synced.
-			h.AssertActiveNodesSyncedTo(block)
+			h.AssertActiveNodesSyncedTo(block.BlockHash())
 
 			// Mine the next block.
 			continue
@@ -116,7 +116,7 @@ func (h *HarnessTest) MineBlocksAndAssertNumTxes(num uint32,
 
 	// Finally, make sure all the active nodes are synced.
 	bestBlock := blocks[len(blocks)-1]
-	h.AssertActiveNodesSyncedTo(bestBlock)
+	h.AssertActiveNodesSyncedTo(bestBlock.BlockHash())
 
 	return blocks
 }
@@ -157,7 +157,7 @@ func (h *HarnessTest) cleanMempool() {
 		bestBlock = blocks[len(blocks)-1]
 
 		// Make sure all the active nodes are synced.
-		h.AssertActiveNodesSyncedTo(bestBlock)
+		h.AssertActiveNodesSyncedTo(bestBlock.BlockHash())
 
 		return fmt.Errorf("still have %d txes in mempool", len(mem))
 	}, wait.MinerMempoolTimeout)