S15: sm-leaf health HTTP, verae.sm.* acks, systemd unit

Loopback GET /health, nats-leaf:// rewrite, subject request-reply tests.
Do not replace pfc-py-admin. NpeRequired stays on the package surface.

go/internal/leaf/leaf_test.go

@@ -1,6 +1,12 @@
 package leaf
 
-import "testing"
+import (
+	"encoding/json"
+	"io"
+	"net/http/httptest"
+	"testing"
+	"time"
+)
 
 func TestStartInProcess(t *testing.T) {
 	n, err := Start("")
@@ -12,3 +18,57 @@ func TestStartInProcess(t *testing.T) {
 		t.Fatal("empty addr")
 	}
 }
+
+func TestParseHubLeafScheme(t *testing.T) {
+	u, err := ParseHub("nats-leaf://10.10.10.21:7422")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if u.Scheme != "nats" {
+		t.Fatalf("scheme %s", u.Scheme)
+	}
+	if u.Host != "10.10.10.21:7422" {
+		t.Fatalf("host %s", u.Host)
+	}
+}
+
+func TestHealthHandler(t *testing.T) {
+	srv := httptest.NewServer(HealthHandler())
+	defer srv.Close()
+	resp, err := srv.Client().Get(srv.URL + "/health")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+	body, _ := io.ReadAll(resp.Body)
+	var m map[string]any
+	if err := json.Unmarshal(body, &m); err != nil {
+		t.Fatal(err)
+	}
+	if m["ok"] != true || m["service"] != "sm-leaf" {
+		t.Fatalf("health %s", body)
+	}
+}
+
+func TestSMSubjectsAck(t *testing.T) {
+	n, err := Start("")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer n.Shutdown()
+	cases := map[string]string{
+		"verae.sm.send":        `{"accepted":true}`,
+		"verae.sm.dead":        `{"queued":true}`,
+		"verae.sm.error":       `{"emitted":true}`,
+		"verae.sm.log.summary": `{"logged":true}`,
+	}
+	for subj, want := range cases {
+		msg, err := n.nc.Request(subj, []byte(`{"lookup_id":"t"}`), time.Second)
+		if err != nil {
+			t.Fatalf("%s: %v", subj, err)
+		}
+		if string(msg.Data) != want {
+			t.Fatalf("%s got %s want %s", subj, msg.Data, want)
+		}
+	}
+}