Write device aliases as startup metadata

internal/pipeline/service_test.go

@@ -43,6 +43,18 @@ func (writer *fakeWriter) firstBatch() []model.Record {
 	return writer.batches[0]
 }
 
+func (writer *fakeWriter) allBatches() [][]model.Record {
+	writer.mu.Lock()
+	defer writer.mu.Unlock()
+
+	copyBatches := make([][]model.Record, 0, len(writer.batches))
+	for _, batch := range writer.batches {
+		copyBatches = append(copyBatches, append([]model.Record(nil), batch...))
+	}
+
+	return copyBatches
+}
+
 func TestServiceFlushesParsedRecords(t *testing.T) {
 	fake := newFakeWriter()
 	service := NewService(config.Config{
@@ -66,6 +78,12 @@ func TestServiceFlushesParsedRecords(t *testing.T) {
 		errCh <- service.Run(ctx)
 	}()
 
+	select {
+	case <-fake.flushed:
+	case <-time.After(2 * time.Second):
+		t.Fatal("timed out waiting for alias metadata flush")
+	}
+
 	service.Enqueue(model.RawMessage{
 		Topic:      "tele/tasmota_896001/LWT",
 		Payload:    []byte("Online"),
@@ -83,7 +101,23 @@ func TestServiceFlushesParsedRecords(t *testing.T) {
 		t.Fatal("timed out waiting for pipeline flush")
 	}
 
-	batch := fake.firstBatch()
+	batches := fake.allBatches()
+	if len(batches) != 2 {
+		t.Fatalf("expected 2 flushed batches, got %d", len(batches))
+	}
+
+	metaBatch := batches[0]
+	if len(metaBatch) != 2 {
+		t.Fatalf("expected 2 alias metadata records, got %d", len(metaBatch))
+	}
+	if metaBatch[0].Measurement != "tasmota_device_meta" {
+		t.Fatalf("unexpected metadata measurement: %s", metaBatch[0].Measurement)
+	}
+	if metaBatch[0].Fields["device_alias"] == "" {
+		t.Fatalf("expected metadata batch to include device_alias, got %#v", metaBatch[0].Fields["device_alias"])
+	}
+
+	batch := batches[1]
 	if len(batch) != 2 {
 		t.Fatalf("expected 2 records in flushed batch, got %d", len(batch))
 	}