sweepbatcher: test that empty batches won't prevent startup

Author: bhandras

sweepbatcher/sweep_batcher.go

@@ -153,6 +153,10 @@ type Batcher struct {
 	// quit signals that the batch must stop.
 	quit chan struct{}
 
+	// initDone is a channel that is closed when the batcher has been
+	// initialized.
+	initDone chan struct{}
+
 	// wallet is the wallet kit client that is used by batches.
 	wallet lndclient.WalletKitClient
 
@@ -200,6 +204,7 @@ func NewBatcher(wallet lndclient.WalletKitClient,
 		sweepReqs:        make(chan SweepRequest),
 		errChan:          make(chan error, 1),
 		quit:             make(chan struct{}),
+		initDone:         make(chan struct{}),
 		wallet:           wallet,
 		chainNotifier:    chainNotifier,
 		signerClient:     signerClient,
@@ -239,6 +244,9 @@ func (b *Batcher) Run(ctx context.Context) error {
 		}
 	}
 
+	// Signal that the batcher has been initialized.
+	close(b.initDone)
+
 	for {
 		select {
 		case sweepReq := <-b.sweepReqs:

sweepbatcher/sweep_batcher_test.go

@@ -3,6 +3,7 @@ package sweepbatcher
 import (
 	"context"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
@@ -1029,3 +1030,38 @@ func TestGetFeePortionForSweep(t *testing.T) {
 		})
 	}
 }
+
+// TestRestoringEmptyBatch tests that the batcher can be restored with an empty
+// batch.
+func TestRestoringEmptyBatch(t *testing.T) {
+	defer test.Guard(t)()
+
+	lnd := test.NewMockLnd()
+	ctx, cancel := context.WithCancel(context.Background())
+
+	store := loopdb.NewStoreMock(t)
+
+	batcherStore := NewStoreMock()
+	_, err := batcherStore.InsertSweepBatch(ctx, &dbBatch{})
+	require.NoError(t, err)
+
+	batcher := NewBatcher(lnd.WalletKit, lnd.ChainNotifier, lnd.Signer,
+		testMuSig2SignSweep, nil, lnd.ChainParams, batcherStore, store)
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+
+	go func() {
+		defer wg.Done()
+		err = batcher.Run(ctx)
+	}()
+
+	// Wait for the batcher to be initialized.
+	<-batcher.initDone
+
+	// Now make it quit by canceling the context.
+	cancel()
+	wg.Wait()
+
+	require.Error(t, context.Canceled, err)
+}