fs.readFileSync() causes tests to hang

🐛 bug report

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Description of the problem

Cannot use fs.readFileSync() in tests

How has this issue affected you? What are you trying to accomplish?

I would like to write unit tests for a Vanilla Javascript project. To do that I need to read the index.html file into my test file.

To Reproduce

import fs from "fs";
const html = fs.readFileSync("index.html", "utf-8");

In src/index.tests.js causes the tests to hang. In src/index.js it works just fine.

Link to sandbox: link

Your Environment

Start by reproducing the hang from src/index.tests.js using the linked CodeSandbox, then compare it with the working use in src/index.js. Trace how fs.readFileSync() is handled in the test environment and determine whether the test should complete while reading index.html; verify the result by rerunning the affected test.