unistore: close event stream on context cancelation (#101293)

* add tests for broacaster

* fix sql notifier not closing the stream

* fix sql notifier not closing the stream

* close sub

* fix broadcaster test

* fix broadcaster test

* suggestion

pkg/storage/unified/resource/broadcaster_test.go

@@ -104,3 +104,41 @@ func TestCache(t *testing.T) {
 	// slice should return all values
 	require.Equal(t, []int{4, 5, 6, 7, 8, 9, 10, 11, 12, 13}, c.Slice())
 }
+
+func TestBroadcaster(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	ch := make(chan int)
+	input := []int{1, 2, 3}
+	go func() {
+		for _, v := range input {
+			ch <- v
+		}
+	}()
+	t.Cleanup(func() {
+		close(ch)
+	})
+
+	b, err := NewBroadcaster(ctx, func(out chan<- int) error {
+		go func() {
+			for v := range ch {
+				out <- v
+			}
+		}()
+		return nil
+	})
+	require.NoError(t, err)
+
+	sub, err := b.Subscribe(ctx)
+	require.NoError(t, err)
+
+	for _, expected := range input {
+		v, ok := <-sub
+		require.True(t, ok)
+		require.Equal(t, expected, v)
+	}
+
+	// cancel the context should close the stream
+	cancel()
+	_, ok := <-sub
+	require.False(t, ok)
+}