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React Testing: Act and Assert

2. Act

act

Extends the testing util from React

When to use act?

Firing events

userEvent vs fireEvent

userEvent

  • simulates a user
  • clicking a button will focus the button
  • everything is async/await
await user.click(screen.getByRole("button", { name: /click me!/i }));

fireEvent

  • triggers the DOM event
  • clicking a button won't focus

3. Assert in Test

expect(button).toHaveStyle(`
  background-color: white;
  color: black
`);

Last update: 2022-11-04