Extend H8 with a placement candidate the node answers same and applies nothing for, and pin mesh-sdk's group head (issue 1126)

cmd/mesh-host/nodeagent_integration_test.go

@@ -113,7 +113,7 @@ func (b *itBed) start(trustOperator bool) (stop func()) {
 		}
 	}
 	b.session = &link.Session{Membership: link.Membership{Node: itNode}, Timeout: 2 * time.Second,
-		Say: b.say}
+		Say: b.say, Keys: func() link.RecordKeys { return link.RecordKeys{} }}
 	b.session.Attach(context.Background(), link.OverNATS{Conn: b.conn, JS: b.js, Node: itNode})
 	ctx, cancel := context.WithCancel(context.Background())
 	done := make(chan struct{})
@@ -316,7 +316,8 @@ func TestNatsTheHandPathAppliesACompositionTheOperatorSigned(t *testing.T) {
 // Issue 1126 (ADR 0547 §2, the milestone's H8): the node agent started whole against a real bus, once the catalogue
 // places its node (the placement written after it started), composes a module from its want, the indexer's manifest, its record and its mesh-config value, and applies it,
 // with no key in the controller's compositions; a changed config value is composed again on its event and applied as a
-// revision of what runs.
+// revision of what runs. And a catalogue pull request's placement candidate equal to its placement is answered "same"
+// in the node's own key, and nothing is applied for it (ADR 0559 §4, subtask 10 of the milestone).
 func TestNatsANodeThePlacementNamesComposesAndAppliesItsOwn(t *testing.T) {
 	b := newItBed(t)
 	kvOf := func(bucket string) nats.KeyValue {
@@ -329,6 +330,11 @@ func TestNatsANodeThePlacementNamesComposesAndAppliesItsOwn(t *testing.T) {
 	placement, modules, manifests := kvOf(delivery.PlacementBucket), kvOf(delivery.ModulesBucket), kvOf(delivery.ManifestsBucket)
 	resolved := kvOf(selfcompose.ResolvedBucket)
 	kvOf(delivery.BuilderBuildsBucket)
+	candidates := kvOf(delivery.PlacementCandidatesBucket)
+	// The controller's stream the node's facts go into, so the node's key carries the facts it says.
+	if _, err := b.js.AddStream(&nats.StreamConfig{Name: "CONTROL", Subjects: []string{link.ReportSubject(itNode)}}); err != nil {
+		t.Fatal(err)
+	}
 	path := filepath.Join(b.dir, "web.conf")
 	man := `{"module":"web","version":"1","config":{"greeting":{"type":"string","description":"what the file says","default":"hello"}},` +
 		`"resources":[{"id":"conf","type":"file","path":"` + path + `","mode":"0644","content":"greeting=${config:greeting}\n"}]}`
@@ -385,4 +391,37 @@ func TestNatsANodeThePlacementNamesComposesAndAppliesItsOwn(t *testing.T) {
 		h := b.have("web")
 		return h.FP == fp && h.Composed != first && h.Phase == delivery.PhaseRunning
 	})
+
+	// The node says its facts (its record, as the test wrote it), then a candidate equal to its placement is written: the
+	// node answers "same" at the candidate's head and revision in its own key, and applies nothing.
+	b.session.SayFacts(context.Background(), link.Report{Profile: map[string]any{"capabilities": []any{
+		map[string]any{"name": "service-manager", "present": true}}}})
+	second := b.have("web").Composed
+	same, _ := delivery.DecodePlacement(place)
+	craw, err := delivery.EncodePlacementCandidate(delivery.PlacementCandidate{Group: "feat/x",
+		Pull: delivery.Head{Repository: delivery.CatalogueRepository, Number: 1, Head: "h1"}, Placement: &same})
+	if err != nil {
+		t.Fatal(err)
+	}
+	ckey, _ := delivery.PlacementCandidateKey("feat/x", itNode)
+	crev, err := candidates.Put(ckey, craw)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var answer delivery.CandidateAnswer
+	within(t, 10*time.Second, "the node did not answer its candidate", func() bool {
+		e, err := b.haves.Get(hkey)
+		if err != nil {
+			return false
+		}
+		n, err := delivery.DecodeHaveNode(e.Value())
+		answer = n.Candidates["feat/x"]
+		return err == nil && answer.Head == "h1" && n.Record != nil
+	})
+	if answer.Verdict != delivery.CandidateSame || answer.Revision != crev || len(answer.Same) != 1 || answer.Same[0] != "web" {
+		t.Errorf("the answer to a candidate equal to the placement: %+v", answer)
+	}
+	if h := b.have("web"); h.Composed != second || b.file("web") != "greeting=salut\n" {
+		t.Errorf("a candidate moved what runs: %+v, %q", h, b.file("web"))
+	}
 }