mocha test problem in Ubuntu:ReferenceError: ert is not defined - node.js

Question

I am using mocha to test my node js code. While running on windows machine, I am able to test my application successfully. But when I am trying to test same application project in Ubuntu , I am getting ReferenceError: ert is not defined . So i did "rm -rf node_modes" and "npm i" again . But the issue still persist.
Error in terminal
$ npm test
> myapplication#1.0.0 test /NodeProject/MyApplication
> mocha Test/* --require #babel/register
/NodeProject/MyApplication/node_modules/yargs/yargs.js:1163
else throw err
^
ReferenceError: ert is not defined
at Object.<anonymous> (/NodeProject/MyApplication/Test/app.test.js:1:4)
at Module._compile (internal/modules/cjs/loader.js:776:30)
at Module._compile (/NodeProject/MyApplication/node_modules/pirates/lib/in dex.js:99:24)
at Module._extensions..js (internal/modules/cjs/loader.js:787:10)
at Object.newLoader [as .js] (/NodeProject/MyApplication/node_modules/pira tes/lib/index.js:104:7)
at Module.load (internal/modules/cjs/loader.js:653:32)
at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
at Function.Module._load (internal/modules/cjs/loader.js:585:3)
at Module.require (internal/modules/cjs/loader.js:690:17)
at require (internal/modules/cjs/helpers.js:25:18)
at /NodeProject/MyApplication/node_modules/mocha/lib/mocha.js:330:36
at Array.forEach (<anonymous>)
at Mocha.loadFiles (/NodeProject/MyApplication/node_modules/mocha/lib/moch a.js:327:14)
at Mocha.run (/NodeProject/MyApplication/node_modules/mocha/lib/mocha.js:8 04:10)
at Object.exports.singleRun (/NodeProject/MyApplication/node_modules/mocha /lib/cli/run-helpers.js:207:16)
at exports.runMocha (/NodeProject/MyApplication/node_modules/mocha/lib/cli /run-helpers.js:300:13)
at Object.exports.handler.argv [as handler] (/NodeProject/MyApplication/no de_modules/mocha/lib/cli/run.js:296:3)
at Object.runCommand (/NodeProject/MyApplication/node_modules/yargs/lib/co mmand.js:242:26)
at Object.parseArgs [as _parseArgs] (/NodeProject/MyApplication/node_modul es/yargs/yargs.js:1087:28)
at Object.parse (/NodeProject/MyApplication/node_modules/yargs/yargs.js:56 6:25)
at Object.exports.main (/NodeProject/MyApplication/node_modules/mocha/lib/ cli/cli.js:63:6)
at Object.<anonymous> (/NodeProject/MyApplication/node_modules/mocha/bin/_ mocha:10:23)
at Module._compile (internal/modules/cjs/loader.js:776:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)
at Module.load (internal/modules/cjs/loader.js:653:32)
at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
at Function.Module._load (internal/modules/cjs/loader.js:585:3)
at Function.Module.runMain (internal/modules/cjs/loader.js:829:12)
at startup (internal/bootstrap/node.js:283:19)
at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)
npm ERR! Test failed. See above for more details.
And here is my app.test.js file
var assert = require('assert')
, expect = require('expect.js'),
W3CWebSocket = require('websocket').w3cwebsocket;
describe('Test Suite', function() {
var client;
beforeEach(function(done) {
client = new W3CWebSocket('ws://localhost:8091/', 'echo-protocol');
client.onopen = function() {
console.log('WebSocket Client Connected');
done();
};
client.onclose = function() {
console.log('echo-protocol Client Closed');
};
});
afterEach(function(done) {
if(client!=null){
client.close();
}
done();
});
it('My App result', (done) => {
if (client.readyState === client.OPEN) {
client.send(`"data":"dummy"}`);
}
client.onmessage = function(e) {
let data = e.data;
expect(data).to.not.equal(null);
expect(data).to.not.equal(undefined);
done();
};
});
});

Answer 1

I faced similar issue. It was because babel version in package.json is different from the one whose specific settings are set in .babelrc file
Try deleting .babelrc file and see if it works.
The ert probably is from
.../node_modules/babel-core/lib/transformation/file/options/option-manager.js:128
log.error or log.ert
If not search whole directory for ert, that should give you some clue