fix readiness router health contract

internal/admin/admin.go

@@ -67,10 +67,9 @@ func (s *Server) authorize(r *http.Request) error {
 }
 
 func (s *Server) Readiness(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
 	checks := []Probe{{Name: "store", Ready: s.Store != nil}}
-	if s.RouterReady {
-		checks = append(checks, Probe{Name: "router", Ready: true})
-	}
+	checks = append(checks, Probe{Name: "router", Ready: s.RouterReady})
 	for name, probe := range s.Probes {
 		ok, detail := probe()
 		checks = append(checks, Probe{Name: name, Ready: ok, Detail: detail})

internal/admin/admin_test.go

@@ -3,6 +3,7 @@ package admin
 import (
 	"context"
 	"encoding/json"
+	"net/http"
 	"net/http/httptest"
 	"orchestra/internal/authz"
 	"orchestra/internal/domain"
@@ -11,6 +12,45 @@ import (
 	"testing"
 )
 
+func TestReadinessRequiresRouterAndReturnsJSON(t *testing.T) {
+	s, err := store.Open(t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	h := (&Server{Store: s, RouterReady: false}).Readiness
+	r := httptest.NewRequest(http.MethodGet, "/readyz", nil)
+	w := httptest.NewRecorder()
+	h(w, r)
+	if w.Code != http.StatusServiceUnavailable {
+		t.Fatalf("status=%d body=%s", w.Code, w.Body)
+	}
+	if got := w.Header().Get("Content-Type"); got != "application/json" {
+		t.Fatalf("content type=%q", got)
+	}
+	var body struct {
+		Ready  bool    `json:"ready"`
+		Checks []Probe `json:"checks"`
+	}
+	if err := json.Unmarshal(w.Body.Bytes(), &body); err != nil {
+		t.Fatal(err)
+	}
+	if body.Ready || len(body.Checks) != 2 || body.Checks[1].Name != "router" || body.Checks[1].Ready {
+		t.Fatalf("readiness=%+v", body)
+	}
+}
+
+func TestReadinessSucceedsWhenStoreAndRouterReady(t *testing.T) {
+	s, err := store.Open(t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	w := httptest.NewRecorder()
+	(&Server{Store: s, RouterReady: true}).Readiness(w, httptest.NewRequest(http.MethodGet, "/readyz", nil))
+	if w.Code != http.StatusOK || !strings.Contains(w.Body.String(), `"ready":true`) {
+		t.Fatalf("status=%d body=%s", w.Code, w.Body)
+	}
+}
+
 func TestDiagnosticsRequiresFullControl(t *testing.T) {
 	s, err := store.Open(t.TempDir())
 	if err != nil {