fix syncer test

sync/sync_test.go

@@ -303,7 +303,7 @@ func TestSync_InvalidSyncTarget(t *testing.T) {
 	head := suite.Head()
 
 	// create a local store which is initialised at genesis height
-	localStore := newTestStore(t, ctx, head)
+	localStore := newTestStore(t, ctx, head, store.WithWriteBatchSize(10))
 	// create a peer which is already on height 100
 	remoteStore := headertest.NewStore(t, suite, 100)
 
@@ -347,7 +347,14 @@ func TestSync_InvalidSyncTarget(t *testing.T) {
 	// ensure syncer could only sync up to one header below the bad sync target
 	h, err := localStore.Head(ctx)
 	require.NoError(t, err)
-	require.Equal(t, maliciousHeader.Height()-1, h.Height())
+
+	// we need to wait for a flush
+	assert.Eventually(t, func() bool {
+		h, err = localStore.Head(ctx)
+		require.NoError(t, err)
+
+		return maliciousHeader.Height()-1 == h.Height()
+	}, time.Second, 100*time.Millisecond)
 
 	// manually change bad sync target to a good header in remote peer
 	// store so it can re-serve it to syncer once it re-requests the height
@@ -400,7 +407,7 @@ func (d *delayedGetter[H]) GetRangeByHeight(ctx context.Context, from H, to uint
 }
 
 // newTestStore creates initialized and started in memory header Store which is useful for testing.
-func newTestStore(tb testing.TB, ctx context.Context, head *headertest.DummyHeader) header.Store[*headertest.DummyHeader] {
+func newTestStore(tb testing.TB, ctx context.Context, head *headertest.DummyHeader, opts ...store.Option) header.Store[*headertest.DummyHeader] {
 	ds := sync.MutexWrap(datastore.NewMapDatastore())
-	return store.NewTestStore(tb, ctx, ds, head)
+	return store.NewTestStore(tb, ctx, ds, head, opts...)
 }