`@remix-run/testing`

This package contains utilities to assist in unit testing portions of your Remix application. This is accomplished by mocking the Remix route modules/assets manifest output by the compiler and generating an in-memory React Router app via createMemoryRouter.

The general usage of this is to test components/hooks that rely on Remix hooks/components which you do not have the ability to cleanly mock (useLoaderData, useFetcher, etc.). While it can also be used for more advanced testing such as clicking links and navigating to pages, those are better suited for End-to-End tests via something like Cypress or Playwright.

Usage

To use createRemixStub, define your routes using React Router-like route objects, where you specify the path, Component, loader, etc. These are essentially mocking the nesting and exports of the route files in your Remix app:

import { createRemixStub } from "@remix-run/testing";

const RemixStub = createRemixStub([
  {
    path: "/",
    Component: MyComponent,
    loader() {
      return json({ message: "hello" });
    },
  },
]);

Then you can render the <RemixStub /> component and assert against it:

render(<RemixStub />);
await waitFor(() =>
  screen.findByText("Some rendered text")
);

Example

Here's a full working example testing using jest and React Testing Library:

import { json } from "@remix-run/node";
import { useLoaderData } from "@remix-run/react";
import { createRemixStub } from "@remix-run/testing";
import {
  render,
  screen,
  waitFor,
} from "@testing-library/react";

test("renders loader data", async () => {
  // ⚠️ This would usually be a component you import from your app code
  function MyComponent() {
    const data = useLoaderData() as { message: string };
    return <p>Message: {data.message}</p>;
  }

  const RemixStub = createRemixStub([
    {
      path: "/",
      Component: MyComponent,
      loader() {
        return json({ message: "hello" });
      },
    },
  ]);

  render(<RemixStub />);

  await waitFor(() => screen.findByText("Message: hello"));
});