How to stream test to mocha via console (stdin)?

Question

JavaScript

You need to stream the mocha file through the console, i.e. first collect the test with a bundler, and then stream it to mocha, without intermediate writing to disk:
rollup -f cjs test.js>mocha
rollup the stream returns, but it doesn’t look like mocha can count, no errors at all... can it really not read stdin?