Example code for the blog post at https://ph-fritsche.github.io/blog/post/react-act

Clone the repository and install dependencies

git clone https://github.com/ph-fritsche/example-react-act.git
cd example-react-act
yarn

Serve the example

yarn start

Run the tests

yarn test

Trigger the warning

Edit src/MyCounter.test.tsx:

        vi.spyOn(defaultStore, 'sync')
            .mockImplementationOnce(() => Promise.resolve()
                // Just enough microtasks for this setup.
                // Comment this out to add a warning.
                .then(() => void 0)
                .then(() => void 0)
            )