unit-testing javascript files

[#1]

I have read this article
https://community.apigee.com/articles/3964/unit-testing-javascript-code-with-mocha-sinon-and.html

like the one from the article for example

try {
    var responseCode = parseInt(context.getVariable('response.status.code'));

    var log = {
        org: context.getVariable('organization.name'),
        env: context.getVariable('environment.name'),
        responseCode: responseCode,
        isError: (responseCode >= 400)
    };

    if (log.isError) {
        log.errorMessage = context.getVariable('flow.error.message');
    }

    var logglyRequest = new Request(
        'https://loggly.com/aaa',
        'POST',
        {'Content-Type': 'application/json'},
        JSON.stringify(log)
    );
    httpClient.send(logglyRequest);
} catch (e) {}

The thing is that when I try to 'require' the js file I get nothing.
And only when I add 'module.exports' I get the file.

1. Am I not importing this the right way?
2. The problem is that apigee js object model doesn't recognize 'module.exports' so I cant leave it that way. what should I do?