fix(unified-storage): enable in-process events for single-instance (#100807)

pkg/storage/unified/sql/notifier_test.go

@@ -0,0 +1,71 @@
+package sql
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/storage/unified/resource"
+	"github.com/stretchr/testify/require"
+)
+
+func TestChannelNotifier(t *testing.T) {
+	t.Run("should notify subscribers of events", func(t *testing.T) {
+		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+		defer cancel()
+
+		n := newChannelNotifier(5, log.NewNopLogger())
+
+		events, err := n.notify(ctx)
+		require.NoError(t, err)
+
+		testEvent := &resource.WrittenEvent{
+			Type: resource.WatchEvent_ADDED,
+			Key: &resource.ResourceKey{
+				Group:     "test",
+				Resource:  "test",
+				Name:      "test1",
+				Namespace: "test",
+			},
+			ResourceVersion: 1,
+		}
+		n.send(ctx, testEvent)
+
+		select {
+		case event := <-events:
+			require.Equal(t, testEvent, event)
+		case <-ctx.Done():
+			t.Fatal("timeout waiting for event")
+		}
+	})
+
+	t.Run("should drop events when buffer is full", func(t *testing.T) {
+		bufferSize := 2
+		n := newChannelNotifier(bufferSize, log.NewNopLogger())
+
+		events, err := n.notify(context.Background())
+		require.NoError(t, err)
+
+		for i := 0; i < bufferSize+1; i++ {
+			n.send(context.Background(), &resource.WrittenEvent{
+				ResourceVersion: int64(i),
+			})
+		}
+
+		require.Equal(t, bufferSize, len(events))
+	})
+
+	t.Run("should close subscriber channels when context cancelled", func(t *testing.T) {
+		ctx, cancel := context.WithCancel(context.Background())
+		n := newChannelNotifier(5, log.NewNopLogger())
+
+		events, err := n.notify(ctx)
+		require.NoError(t, err)
+
+		cancel()
+
+		_, ok := <-events
+		require.False(t, ok, "channel should be closed")
+	})
+}