Implementing more advanced feature: audit and more

internal/datasource/servervar/servervar_test.go

@@ -0,0 +1,74 @@
+package servervar
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/uopi/uopi/internal/datasource"
+)
+
+func TestWriteSubscribePersist(t *testing.T) {
+	dir := t.TempDir()
+	s, err := New(dir)
+	if err != nil {
+		t.Fatalf("New: %v", err)
+	}
+	ctx := context.Background()
+
+	if err := s.Write(ctx, "seq_state", 3.0); err != nil {
+		t.Fatalf("Write: %v", err)
+	}
+
+	// Subscribe should deliver the current value immediately.
+	ch := make(chan datasource.Value, 4)
+	cancel, err := s.Subscribe(ctx, "seq_state", ch)
+	if err != nil {
+		t.Fatalf("Subscribe: %v", err)
+	}
+	defer cancel()
+	select {
+	case v := <-ch:
+		if got := v.Data.(float64); got != 3.0 {
+			t.Fatalf("initial value = %v, want 3", got)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("no initial value delivered")
+	}
+
+	// A later write fans out to the subscriber.
+	if err := s.Write(ctx, "seq_state", 7.0); err != nil {
+		t.Fatalf("Write 2: %v", err)
+	}
+	select {
+	case v := <-ch:
+		if got := v.Data.(float64); got != 7.0 {
+			t.Fatalf("updated value = %v, want 7", got)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("no update delivered")
+	}
+
+	// ListSignals reports the variable.
+	sigs, err := s.ListSignals(ctx)
+	if err != nil || len(sigs) != 1 || sigs[0].Name != "seq_state" {
+		t.Fatalf("ListSignals = %+v, err %v", sigs, err)
+	}
+
+	// A fresh store over the same dir recovers the last value.
+	s2, err := New(dir)
+	if err != nil {
+		t.Fatalf("reopen: %v", err)
+	}
+	ch2 := make(chan datasource.Value, 1)
+	cancel2, _ := s2.Subscribe(ctx, "seq_state", ch2)
+	defer cancel2()
+	select {
+	case v := <-ch2:
+		if got := v.Data.(float64); got != 7.0 {
+			t.Fatalf("persisted value = %v, want 7", got)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("persisted value not delivered")
+	}
+}