Extend E2E assertions

frontend/test-client/src/utils/test-error-tracker.ts

@@ -0,0 +1,25 @@
+export class TestErrorTracker {
+    private firstError: { agentName: string; message: string } | null = null;
+
+    public recordError(agentName: string, message: string): void {
+        this.firstError ??= { agentName, message };
+    }
+
+    /**
+     * If an error was recorded, throw it. Call this at natural checkpoints:
+     * after each iteration, before assertions, etc.
+     */
+    public checkAndThrow(): void {
+        if (this.firstError !== null) {
+            const { agentName, message } = this.firstError;
+            throw new Error(
+                `ERROR-level log from ${agentName}: ${message}`
+            );
+        }
+    }
+
+    /** Clear recorded errors. Call at the start of each test. */
+    public reset(): void {
+        this.firstError = null;
+    }
+}

frontend/test-client/src/utils/with-timeout.ts

@@ -1,3 +1,10 @@
+export class TimeoutError extends Error {
+    public constructor(message: string) {
+        super(message);
+        this.name = "TimeoutError";
+    }
+}
+
 export async function withTimeout<T>(
     promise: Promise<T>,
     timeoutMs: number,
@@ -8,7 +15,9 @@ export async function withTimeout<T>(
         new Promise<T>((_, reject) =>
             setTimeout(() => {
                 reject(
-                    new Error(`${operationName} timed out after ${timeoutMs}ms`)
+                    new TimeoutError(
+                        `${operationName} timed out after ${timeoutMs}ms`
+                    )
                 );
             }, timeoutMs)
         )