views: an owner's changes are ordinary events on the shared events stream, heard on the reader's one durable consumer; Follow takes no stream, Other takes the rest (ADR 0635 §5, D-25; issue 1966)

Claude-Session: https://claude.ai/code/session_01NcbgfFSnn24M3GcqttoU7i

go/views/process_reader_integration_test.go

@@ -0,0 +1,80 @@
+//go:build integration
+
+package views_test
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"github.com/nats-io/nats.go/jetstream"
+
+	"git.novox.be/novox/mesh-sdk/go/process"
+	"git.novox.be/novox/mesh-sdk/go/testbus"
+	"git.novox.be/novox/mesh-sdk/go/views"
+	"git.novox.be/novox/mesh-sdk/go/views/viewstest"
+)
+
+// An owner's change is an ordinary event on the shared events stream (novox/hq ADR 0635 §5): a reader that follows the
+// owner's state by its read tool hears it on the module's durable consumer of that stream, with no stream of the owner's,
+// and a message that is no views event goes to Other.
+func TestAReaderHearsAnOwnersChangesAsOrdinaryEvents(t *testing.T) {
+	nc, err := nats.Connect(testbus.URL(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer nc.Close()
+	js, err := jetstream.New(nc)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	cred := process.Account{Node: "n1", Module: "reader"}
+	kv := viewstest.Serve(t, ctx, js, nc, "o", "modules", "o.o_read_modules", cred.EventConsumerName())
+	if _, err := kv.Put(ctx, "a", []byte(`{"n":1}`)); err != nil {
+		t.Fatal(err)
+	}
+	other := make(chan string, 1)
+	r := &views.ProcessReader{Module: "reader", Other: func(m jetstream.Msg) { other <- m.Subject(); _ = m.Ack() }, Logf: t.Logf,
+		Call: func(tool string, body any) (json.RawMessage, error) {
+			raw, _ := json.Marshal(body)
+			m, err := nc.Request("mesh.mod.o.call.o_read_modules.n0", raw, 5*time.Second)
+			if err != nil {
+				return nil, err
+			}
+			return m.Data, nil
+		}}
+	if _, err := r.Follow("o", "modules", "o.o_read_modules"); err != nil {
+		t.Fatal(err)
+	}
+	r.Start(ctx, js, cred, nil)
+	<-r.Ready()
+	pic, err := r.KeyValue(ctx, "o_modules")
+	if err != nil {
+		t.Fatal(err)
+	}
+	w, err := pic.Watch(ctx, "b")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := kv.Put(ctx, "b", []byte(`{"n":2}`)); err != nil {
+		t.Fatal(err)
+	}
+	for e := range w.Updates() {
+		if e != nil && e.Key() == "b" {
+			break
+		}
+	}
+	if s := r.Followers()[0].Status(); s.Asks != 1 || s.Keys != 2 {
+		t.Fatalf("the change was not heard as an event alone: %+v", s)
+	}
+	if _, err := js.Publish(ctx, "mesh.mod.o.event.something-else", []byte("{}")); err != nil {
+		t.Fatal(err)
+	}
+	if got := <-other; got != "mesh.mod.o.event.something-else" {
+		t.Fatalf("other got %s", got)
+	}
+}