Files
budget2.0/src/ui/components/ErrorBoundary.test.tsx
T
Lucas WintherandClaude Opus 5 da0d1ac35c fix(ui): catch render throws with an error boundary around routed content
A purchase in a currency with no configured exchange rate makes
src/domain/fx.ts throw MissingRateError (correct behavior — never silently
convert at a wrong rate). Nothing caught it: 5 of 6 routes call
monthView/yearView/summaryView and threw during render, and with no error
boundary anywhere in src/, the throw unmounted the entire React tree
including the nav bar. Since the catch-all route redirects to the current
month on first load, one un-rated foreign-currency purchase white-screened
the app immediately on landing, with the only way out (Settings, where the
rate is added) unreachable because the nav was gone too.

Adds RouteErrorBoundary (a class component, as required for
getDerivedStateFromError/componentDidCatch) that renders the thrown
message plus a link to Settings and a "Try again" reset, and
RouteErrorBoundaryReset, a wrapper that keys the boundary on the current
route so it clears on navigation. Wraps only <Routes> in App.tsx, not
<nav>, so navigation stays usable when a route throws.

Also guards the happy-dom per-file GlobalRegistrator.register() call in
registerSw.test.ts and the new ErrorBoundary.test.tsx with
isRegistered, since Bun can run both files in one process.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
2026-09-02 00:57:05 +02:00

113 lines
3.3 KiB
TypeScript

import { GlobalRegistrator } from "@happy-dom/global-registrator";
// Bun can run multiple test files in one process, and registerSw.test.ts
// registers happy-dom globally too — guard so both files can run together.
if (!GlobalRegistrator.isRegistered) {
GlobalRegistrator.register();
}
// Silences React's "environment not configured to support act(...)" warning;
// this file drives React purely through explicit `act()` calls below.
(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
import { test, expect, afterEach } from "bun:test";
import { act } from "react";
import { createRoot, type Root } from "react-dom/client";
import { Link, MemoryRouter, useLocation } from "react-router";
import { RouteErrorBoundary, RouteErrorBoundaryReset } from "./ErrorBoundary.tsx";
let container: HTMLDivElement | null = null;
let root: Root | null = null;
function mount(children: React.ReactNode) {
container = document.createElement("div");
document.body.appendChild(container);
root = createRoot(container);
act(() => {
root!.render(children);
});
return container;
}
afterEach(() => {
if (root) {
act(() => {
root!.unmount();
});
root = null;
}
if (container) {
container.remove();
container = null;
}
});
function Thrower(): never {
throw new Error("No exchange rate configured for EUR");
}
function Fine() {
return <div>all good</div>;
}
test("a throwing child renders the fallback including the thrown message", () => {
const el = mount(
<MemoryRouter>
<RouteErrorBoundary>
<Thrower />
</RouteErrorBoundary>
</MemoryRouter>,
);
expect(el.textContent).toContain("This view could not be displayed");
expect(el.textContent).toContain("No exchange rate configured for EUR");
// The way back to Settings must still be present.
const link = el.querySelector("a[href*='/settings']");
expect(link).not.toBeNull();
// "Try again" control is present to retry without a full reload.
expect(el.textContent).toContain("Try again");
});
test("a non-throwing child renders normally", () => {
const el = mount(
<MemoryRouter>
<RouteErrorBoundary>
<Fine />
</RouteErrorBoundary>
</MemoryRouter>,
);
expect(el.textContent).toContain("all good");
expect(el.textContent).not.toContain("could not be displayed");
});
function View() {
const location = useLocation();
return (
<RouteErrorBoundaryReset>
{location.pathname === "/a" ? <Thrower /> : <Fine />}
</RouteErrorBoundaryReset>
);
}
test("RouteErrorBoundaryReset resets the error state when the route changes", () => {
const el = mount(
<MemoryRouter initialEntries={["/a"]}>
<Link to="/b">go to settings</Link>
<View />
</MemoryRouter>,
);
expect(el.textContent).toContain("No exchange rate configured for EUR");
// A real navigation (e.g. following the boundary's Settings link) changes
// the route; the boundary is keyed on location.pathname, so it should
// remount with a clean error state instead of staying stuck.
const link = el.querySelector("a");
expect(link).not.toBeNull();
act(() => {
link!.dispatchEvent(new MouseEvent("click", { bubbles: true, cancelable: true }));
});
expect(el.textContent).toContain("all good");
expect(el.textContent).not.toContain("could not be displayed");
});