jest-mock-react-noop

Mock React components to noops with Jest.

⚛️:construction::goat:

Remember shallow rendering from enzyme? Wish you could have it with @testing-library/react? Now you can!

Use jest.mock to re-define react as jest-mock-react-noop, providing it with an argument indicating the component(s) under test. jest-mock-react-noop returns a monkeypatched version of React with a modified createElement function. When rendering, any component not under test will be replaced with one that returns a placeholder empty div with a data-jest-mock-react-noop attribute whose value is that component's name.

You can query for placeholder divs using the following query functions (similar to @testing-library's query functions):

• getByNoop
• getAllByNoop
• queryByNoop
• queryAllByNoop

import "@testing-library/jest-dom";
import * as React from "react";
import { renderWithNoop } from "jest-mock-react-noop";
import { App } from "../App";

jest.mock("react", () =>
  // @ts-ignore
  require("jest-mock-react-noop").default('App')
);

describe("App", () => {
  test("works", () => {
    const { queryByNoop } = renderWithNoop(<App />);

    // Assert that a nested component is rendered only as a noop.
    expect(queryByNoop('Other')).toBeInTheDocument();
  });
});

You can match components by name with string:

require("jest-mock-react-noop").default('App')

Or with regular expression:

require("jest-mock-react-noop").default(/App/)

Or with a function returning a boolean (which also gives you access to the component constructor):

require("jest-mock-react-noop").default(
  // `name` is the component name/string
  // `type` is the function/constructor or tag name string
  (name, type) => return ['App', 'MyComponent'].includes(name)
)

If you prefer to configure queries manually and use the native render instead of our renderWithNoop, you can import either noopQueries (with type NoopQueries) or noopQueriesWithDefaults (with type and NoopQueriesWithDefaults, which includes the defaults from @testing-library/react).

import { render, queries } from "@testing-library/react";
import { noopQueries, NoopQueriesWithDefaults} from "..";

describe("App", () => {
  test("works", () => {
    const { queryByNoop, queryByTestId } = render<NoopQueriesWithDefaults>(<App />, {
      queries: {
        ...queries,
        ...noopQueries
      }
    });
  });
});

import { render } from "@testing-library/react";
import { noopQueriesWithDefaults, NoopQueriesWithDefaults} from "..";

describe("App", () => {
  test("works", () => {
    const { queryByNoop, queryByTestId } = render<NoopQueriesWithDefaults>(<App />, {
      queries: noopQueriesWithDefaults
    });
  });
});

Sometimes jest.mock as above won't work, e.g., with ts-jest you might get this error:

TypeError: require(...).default is not a function

If so, you can try this:

jest.mock("react", () => ({
  ...jest.requireActual('react'),
  createElement: jest.fn()
}));

React.createElement.mockImplementation(
  // @ts-ignore
  require('jest-mock-react-noop').default('App').createElement
);