perf: enforce journey budgets and reference traces

tests/helpers/test-build-auth.ts

@@ -97,6 +97,16 @@ export const wrongTokenFaultUrl = (origin: string, fault: PortfolioFaultId): str
   fault,
 );
 
+export const authorizedPerformanceUrl = (origin: string, tier: 'high' | 'low'): string => {
+  const token = process.env.PORTFOLIO_TEST_TOKEN;
+  if (token === undefined) throw new Error('The per-run portfolio test token is unavailable.');
+  const url = new URL(origin);
+  url.searchParams.set('__portfolio_performance', 'drive-trace.v1');
+  url.searchParams.set('__portfolio_test_token', token);
+  url.searchParams.set('__portfolio_tier', tier);
+  return url.href;
+};
+
 export interface BrowserErrorCollector {
   readonly pageErrors: string[];
 }