test(ui): measure workflows and verify shared fetch stability

job-tracker-ui/src/locale-fetch-stability.test.tsx

@@ -0,0 +1,29 @@
+import React from "react";
+import "@testing-library/jest-dom";
+import { fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { MemoryRouter } from "react-router-dom";
+import { api } from "./api";
+import CompaniesTable from "./components/CompaniesTable";
+import { I18nProvider, useI18n } from "./i18n/I18nProvider";
+import { ToastProvider, useToast } from "./toast";
+
+function Actions() {
+  const { toast } = useToast();
+  const { setLanguage } = useI18n();
+  return <><button onClick={() => toast("Saved", "success")}>Show feedback</button><button onClick={() => setLanguage("nb")}>Change language</button></>;
+}
+
+test("feedback does not reload company data; changing locale still reloads translated states", async () => {
+  localStorage.clear();
+  (api.get as jest.Mock).mockResolvedValue({ data: [{ id: 3, name: "Acme" }] });
+  render(<ToastProvider><I18nProvider><MemoryRouter><Actions /><CompaniesTable /></MemoryRouter></I18nProvider></ToastProvider>);
+  await screen.findByRole("button", { name: "Edit: Acme" });
+  const reads = () => (api.get as jest.Mock).mock.calls.filter(([url]) => url === "/companies").length;
+  expect(reads()).toBe(1);
+  fireEvent.click(screen.getByRole("button", { name: "Show feedback" }));
+  expect(await screen.findByRole("alert")).toHaveTextContent("Saved");
+  expect(reads()).toBe(1);
+  fireEvent.click(screen.getByRole("button", { name: "Change language" }));
+  await screen.findByRole("button", { name: "Rediger: Acme" });
+  await waitFor(() => expect(reads()).toBe(2));
+});