Running mocha test but Getting error: ReferenceError: document is not defined

Question

I am using mocha testing framework to test Http rest-api. I want to generate test-report for all test case, but when I ran mocha --reporter html > report.html
Getting following error

/usr/local/lib/node_modules/mocha/lib/reporters/html.js:263
  var div = document.createElement('div');
            ^
ReferenceError: document is not defined
    at fragment (/usr/local/lib/node_modules/mocha/lib/reporters/html.js:263:13)
    at new HTML (/usr/local/lib/node_modules/mocha/lib/reporters/html.js:53:14)
    at Mocha.run (/usr/local/lib/node_modules/mocha/lib/mocha.js:459:18)
    at Object.<anonymous> (/usr/local/lib/node_modules/mocha/bin/_mocha:393:18)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)
    at startup (node.js:119:16)
    at node.js:902:3

Marked

Answer 1

The reporter named html is only to be used when running Mocha in a browser. Running Mocha from the command line won't work with it.

There is a reporter named doc, which outputs "html documentation" according to mocha --reporters. By the way, when you run mocha --reporters you won't see html listed as a reporter, for the reason I've given above.

Meantime

Answer 2

if you don't need to test it in a browser, then you can use jsdom-global:

mocha -r jsdom-global/register

Bhayani

this somehow helped me a lot as otherwise, I don't have any mock for the DOM. Thank you! – Demibastion

Answer 3

You should use a headless browser to avoid this problem. Try with mocha-phantomjs.

Library

This didn't work for me because I'm testing a Node.JS app and Mocha-PhantomJS expects browser-based tests. – Glut

Answer 4

I was able to solve a simpler version of this problem by conditionally defining document:

let document = (typeof document === "undefined") ? {} : document;

I expect you could use the same approach, but would need to set document to something that mocks createElement.

Cookshop

That's not viable. The OP would have to mock not only createElement but getElementsByTagName, getElementById, devicePixeRatio, width, height, getContext, style, className, addEventListener, innerHTML, and many many more. That's a huge task. The HTML reporter expects a full-fledged DOM environment. – Meantime

Oh, I missed that the error is in mocha's code, not the code being tested. That is a harder problem. The principle might still work, I think there are libraries that do mock a (near-)complete DOM, but I'm not sure that counts as "the same approach". – Cookshop