S06-S08: Python spec, Go in-process leaf, tests and Forgejo CI

go/internal/leaf/leaf.go

@@ -0,0 +1,66 @@
+// Package leaf starts an in-process nats-server and optional hub leaf.
+package leaf
+
+import (
+	"errors"
+	"net/url"
+	"time"
+
+	natsserver "github.com/nats-io/nats-server/v2/server"
+	nats "github.com/nats-io/nats.go"
+)
+
+// Node is an in-process broker plus client.
+type Node struct {
+	ns *natsserver.Server
+	nc *nats.Conn
+}
+
+// Start binds 127.0.0.1:0 and optionally leaf-connects to hub.
+func Start(hub string) (*Node, error) {
+	opts := &natsserver.Options{Host: "127.0.0.1", Port: -1}
+	if hub != "" {
+		u, err := url.Parse(hub)
+		if err != nil {
+			return nil, err
+		}
+		opts.LeafNode.Remotes = []*natsserver.RemoteLeafOpts{{URLs: []*url.URL{u}}}
+	}
+	ns, err := natsserver.NewServer(opts)
+	if err != nil {
+		return nil, err
+	}
+	go ns.Start()
+	if !ns.ReadyForConnections(5 * time.Second) {
+		return nil, errors.New("nats not ready")
+	}
+	nc, err := nats.Connect(ns.ClientURL())
+	if err != nil {
+		ns.Shutdown()
+		return nil, err
+	}
+	n := &Node{ns: ns, nc: nc}
+	if _, err := n.nc.Subscribe("verae.sm.send", func(msg *nats.Msg) {
+		if msg.Reply != "" {
+			_ = n.nc.Publish(msg.Reply, []byte(`{"accepted":true}`))
+		}
+	}); err != nil {
+		n.Shutdown()
+		return nil, err
+	}
+	return n, nil
+}
+
+// Addr is the in-process client URL.
+func (n *Node) Addr() string { return n.ns.ClientURL() }
+
+// Shutdown stops client and server.
+func (n *Node) Shutdown() error {
+	if n.nc != nil {
+		n.nc.Close()
+	}
+	if n.ns != nil {
+		n.ns.Shutdown()
+	}
+	return nil
+}

go/internal/leaf/leaf_test.go

@@ -0,0 +1,14 @@
+package leaf
+
+import "testing"
+
+func TestStartInProcess(t *testing.T) {
+	n, err := Start("")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer n.Shutdown()
+	if n.Addr() == "" {
+		t.Fatal("empty addr")
+	}
+}