Markdown Previewer w/ React: test suite shows when loading, then disappears on CodeSandbox

Tell us what’s happening:
i’m trying to run the Test suite on my Markdown Viewer project that I built on CodeSandbox, and the suite shows up for a second and then disappears. I presume this is happening the suite element is maybe being buried under the react components, but I’m not toally sure. Feel free to take a look at my code and the disappearing suite element at the link below.