I added a simple unit test file in codesandbox, this is the project link: https://codesandbox.io/s/muddy-cherry-z9of7?file=/package.json, then I want to use this command to run the unit test:

stanbul cover _mocha ./test/demo.js

but I found the console in codesandbox could not run any commands, no node, no npm, no yarn...... is it possible to run a command in codesandbox? is it possible to write a javascript unit test lib in codesandbox?