Can't install #firebase/testing in firebase CLI - node.js

Question

I was using firebase CLI for testing my cloud firestore security rules and I received the following error while installing #firebase/testing using npm install #firebase/testing --save-dev-
npm WARN deprecated request#2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142
npm WARN deprecated har-validator#5.1.5: this library is no longer supported
> core-js#3.6.5 postinstall E:\Coding\Web\poll-app firebase test\test\node_modules\core-js
> node -e "try{require('./postinstall')}catch(e){}"
internal/modules/cjs/loader.js:967
throw err;
^
Error: Cannot find module 'E:\Coding\Web\poll-app firebase test\test\node_modules\core-js\-e'
at Function.Module._resolveFilename (internal/modules/cjs/loader.js:964:15)
at Function.Module._resolveFilename (pkg/prelude/bootstrap.js:1346:46)
at Function.Module._load (internal/modules/cjs/loader.js:840:27)
at Function.Module.runMain (pkg/prelude/bootstrap.js:1375:12)
at internal/main/run_main_module.js:17:47 {
code: 'MODULE_NOT_FOUND',
requireStack: []
}
npm WARN test#1.0.0 No repository field.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents#2.1.3 (node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents#2.1.3: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! core-js#3.6.5 postinstall: `node -e "try{require('./postinstall')}catch(e){}"`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the core-js#3.6.5 postinstall script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
Can someone tell me what I should be doing?

Answer 1

So, I could fix it by doing the following. I went to my firebase console and opened a cloud shell from security rules playground option. Once it had loaded, I followed the steps given by the learning assistant shown on the right panel and set up my cloud shell by cloning the tutorials from GitHub. Then, I went to quickstart-testing/cs-walkthrough/functions and downloaded the node_modules folder. It was download as a tar file. I ran WinRAR with admin privileges and extracted the tar file. And it worked. I really don't understand how and why it worked but this is what I did to solve the problem.