Address copilot feedback

Author: jamescmartinez

packages/openworkflow/backend.testsuite.ts

@@ -919,7 +919,7 @@ export function testBackend(options: TestBackendOptions): void {
         const updated =
           await backend.rescheduleWorkflowRunAfterFailedStepAttempt({
             workflowRunId: claimed.id,
-            workerId: claimed.workerId ?? "",
+            workerId: claimed.workerId!, // eslint-disable-line @typescript-eslint/no-non-null-assertion
             error,
             availableAt,
           });

packages/openworkflow/execution.test.ts

@@ -610,21 +610,24 @@ function sleep(ms: number): Promise<void> {
 function createMockStepAttempt(
   overrides: Partial<StepAttempt> = {},
 ): StepAttempt {
+  const status = overrides.status ?? "completed";
+
   return {
     namespaceId: "default",
     id: "step-attempt-id",
     workflowRunId: "workflow-run-id",
     stepName: "step",
     kind: "function",
-    status: "completed",
+    status,
     config: {},
     context: null,
     output: null,
     error: null,
     childWorkflowRunNamespaceId: null,
     childWorkflowRunId: null,
     startedAt: new Date("2026-01-01T00:00:00.000Z"),
-    finishedAt: new Date("2026-01-01T00:00:01.000Z"),
+    finishedAt:
+      status === "running" ? null : new Date("2026-01-01T00:00:01.000Z"),
     createdAt: new Date("2026-01-01T00:00:00.000Z"),
     updatedAt: new Date("2026-01-01T00:00:01.000Z"),
     ...overrides,