How do I test 'normal' (non-Node specific) JavaScript functions with Mocha?

Question

This seems like it should be extremely simple; however, after two hours of reading and trial-and-error without success, I'm admitting defeat and asking you guys! I'm trying to use Mocha with Should.js to test some JavaScript functions, but I'm running into scoping issues. I've simplified it down to the most basic of test cases, but I cannot get it working. I have a file named `functions.js`, which just contains the following: ``` function testFunction() { return 1; } ``` And my `tests.js` (located in the same folder) contents: ``` require('./functions.js') describe('tests', function(){ describe('testFunction', function(){ it('should return 1', function(){ testFunction().should.equal(1); }) }) }) ``` This test fails with a `ReferenceError: testFunction is not defined`. I can see why, because most of the examples I've found either attach objects and functions to the Node `global` object or export them using `module.exports`—but using either of these approaches means my function code wou…

Accepted Answer

```
require('./functions.js')
```

That doesn't do anything since you're not exporting anything. What you're expecting is that `testFunction` is globally available, essentially the same as

```
global.testFunction = function() {
    return 1;
}
```

You just can't bypass the export/globals mechanism. It's the way node has been designed. There is no implicit global shared context (like `window` on a browser). Every "global" variable in a module is trapped in it's context.

You should use `module.exports`. If you intend to share that file with a browser environments, there are ways to make it compatible. For a quick hack just do `window.module = {}; jQuery.extend(window, module.exports)` in the browser, or `if (typeof exports !== 'undefined'){ exports.testFunction = testFunction }` for node.

How do I test 'normal' (non-Node specific) JavaScript functions with Mocha?

Solution

Problem