Act warning React testing

Why This Happens

In React, state updates in tests need to be wrapped in act(). This is one of the most common React errors developers encounter. Understanding the root cause helps you fix it quickly and prevent it from recurring.

The Problem

render(<Counter />);
fireEvent.click(button);

The Fix

await act(async () => {
  render(<Counter />);
});
await act(async () => {
  fireEvent.click(button);
});

Step-by-Step Fix

1. 1

   Identify the error

   Look at the error message: Act warning in tests. This tells you exactly what went wrong.

2. 2

   Find the cause

   Check the stack trace to find which line of your React code triggered this error.

3. 3

   Apply the fix

   Use the corrected code pattern shown above. Test to confirm the error is resolved.