MantineProvider + Vitest Bug Test Case

This demonstrates a minimal case to reproduce a bug where MantineProvider does not pass a theme context to an @emotion/styled component when using the component in a vitest unit tests.

Setup

• npm install

Running

• npm run dev to see the component running at http://localhost:5173/
• npm run test:bad to see the test fail when the component is wrapped in a MantineProvider, because theme === {}
• npm run test:good to see the same test pass when the component is wrapped in an emotion ThemeProvider