To use unstated in a Gatsby site you'll need to hook in to two of Gatsby's extension points.
Once in replaceRenderer which runs during Gatsby's server rendering process,
and once in replaceRouterComponent which is part of Gatsby's browser APIs.
Check out ./gatsby-ssr.js and
./gatsby-browser.js to see how this is implemented in this example.
gatsby new example-gatsby-unstated https://github.com/greglobinski/example-gatsby-unstated.git
cd example-gatsby-unstated
gatsby develop
Tests based on jest and react-testing-library
yarn test