fix(app): harden account and workflow state

job-tracker-ui/src/use-view-resource.test.tsx

@@ -0,0 +1,36 @@
+import React from "react";
+import "@testing-library/jest-dom";
+import { act, render, screen } from "@testing-library/react";
+
+import { useViewResource } from "./hooks/useViewResource";
+
+function deferred<T>() {
+  let resolve!: (value: T) => void;
+  const promise = new Promise<T>((next) => { resolve = next; });
+  return { promise, resolve };
+}
+
+it("ignores an older request that completes after a newer dependency load", async () => {
+  const first = deferred<string>();
+  const second = deferred<string>();
+  const load = jest.fn((key: string) => key === "first" ? first.promise : second.promise);
+
+  function Probe({ query }: { query: string }) {
+    const resource = useViewResource(() => load(query), {
+      initialData: "empty",
+      errorMessage: "Unable to load.",
+      deps: [query],
+    });
+    return <div>{resource.data}</div>;
+  }
+
+  const view = render(<Probe query="first" />);
+  view.rerender(<Probe query="second" />);
+
+  await act(async () => { second.resolve("new result"); });
+  expect(screen.getByText("new result")).toBeInTheDocument();
+
+  await act(async () => { first.resolve("stale result"); });
+  expect(screen.getByText("new result")).toBeInTheDocument();
+  expect(screen.queryByText("stale result")).not.toBeInTheDocument();
+});