feat(authz): bind decisions to exact actions

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a02e47-6aac-7ee1-914d-0584c75d3c81

internal/callerauth/tokenreview_test.go

@@ -0,0 +1,46 @@
+package callerauth
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestKubernetesTokenReviewerClassifiesRejectedTokenAsUnauthenticated(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/apis/authentication.k8s.io/v1/tokenreviews" {
+			t.Fatalf("TokenReview path = %q", r.URL.Path)
+		}
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusCreated)
+		_, _ = w.Write([]byte(`{
+  "apiVersion": "authentication.k8s.io/v1",
+  "kind": "TokenReview",
+  "status": {
+    "authenticated": false,
+    "error": "invalid bearer token"
+  }
+}`))
+	}))
+	defer server.Close()
+
+	tokenFile := filepath.Join(t.TempDir(), "reviewer-token")
+	if err := os.WriteFile(tokenFile, []byte("reviewer-token\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	reviewer := &KubernetesTokenReviewer{
+		endpoint:          server.URL + "/apis/authentication.k8s.io/v1/tokenreviews",
+		audience:          "flex-auth",
+		reviewerTokenFile: tokenFile,
+		client:            server.Client(),
+	}
+
+	_, err := reviewer.Review(context.Background(), "malformed")
+	if !errors.Is(err, ErrUnauthenticated) {
+		t.Fatalf("Review error = %v; want unauthenticated", err)
+	}
+}