Testing with Jest

Since FlashList does not immediately render but waits for the size of the underlying ScrollView (unless you specify estimatedListSize), we need to mock triggering onLayout event.

Setup

Add the following line to your jest-setup.js file:

require("@shopify/flash-list/jestSetup");

To be sure, check if your jest.config.js file contains:

...
preset: 'react-native',
setupFiles: ['./jest-setup.js'],
...

Example

Here is an example of using @testing-library/react-native:

import React from "react";
import { render } from "@testing-library/react-native";

describe("MyFlashListComponent", () => {
  it("renders items", () => {
    const { getByText } = render(<MyFlashListComponent />);
    const element = getByText("Title of one of the items");
    // Do something with element ...
  });
});