how do I test a basic javascript file with mocha?

Question

I'm missing something obvious here with Mocha and Coffeescript/Javascript.

I've got a file in /static/js/ called ss.coffee, it's very simple, just one function:

function sortRowCol(a, b) {
    if (a.r == b.r)
        if (a.c == b.c)
            return 0;
        else if (a.c > b.c)
            return 1;
        else return -1;
    else if (a.r > b.r)
        return 1;
    else return -1;
}

The function works correctly, but I decided I needed to start testing this project today, so I put in a mocha test file:

require "../static/js/ss.coffee"

chai = require 'chai'
chai.should()

describe 'SS', ->
    describe '#sortRowCol(a,b)', ->
      it 'should have a sorting function', ->
        f = sortRowCol
        debugger
        console.log 'checking sort row'
        f.should.not.equal(null, "didn't find the sortRowCol function")
    describe 'sortRowCol(a, b)', ->
      it 'should return -1 when first row is less than second', ->
        a = {r: 2, c: "A"}
        b = {r: 1, c: "A"}
        r = sortRowCol a, b
        r.should.equal(-1, "didn't get the correct value")

Something isn't right, because my results are:

 $  mocha --compilers coffee:coffee-script ./test/ss.coffee -R spec           
 SS                                                                      
   #sortRowCol(a,b)                                                              
     1) should have a sorting function                                           
   sortRowCol(a, b)                                                              
     2) should return -1 when first row is less than second                      


 × 2 of 2 tests failed:                                                          

 1) SS #sortRowCol(a,b) should have a sorting function:                 
    ReferenceError: sortRowCol is not defined

It's finding the file correctly, because it will error with 'Cannot find module' if I change that to a non-existent file name.

I tried changing sortRowCol(a,b) to #sortRowCol(a, b) and vice versa, didn't help. The docs (link) don't really explain what that # is doing there, is that just a ruby idiom that's here for some reason?

There must be something wrong with how I'm referencing the ss.coffee file, but I don't see it.

score 12 · Accepted Answer · edited Jul 08 '15 at 03:32

12

By requireing the script in Node, it'll be treated as any other module, isolating sortRowCol as a local within a closure. The script will have to use exports or module.exports to make it available to mocha:

function sortRowCol(a, b) {
    // ...
}

if (typeof module !== 'undefined' && module.exports != null) {
    exports.sortRowCol = sortRowCol;
}

ss = require "../static/js/ss.coffee"
sortRowCol = ss.sortRowCol

# ...

As for...

The docs (link) don't really explain what that # is doing there, [...]

AFAIK, a # is typically used to imply that it's a method -- e.g., Constructor#methodName. Not really sure if that applies here, though.

edited Jul 08 '15 at 03:32

Mike Chamberlain

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answered Jan 07 '13 at 23:28

Jonathan Lonowski

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3

Yep, that did it. Found the answer here http://stackoverflow.com/questions/10204021/how-do-i-test-normal-non-node-specific-javascript-functions-with-mocha while you were writing this answer. I assumed that about the # but it seems very Ruby-ish, doesn't it? Seems a bit out of place. – jcollum Jan 07 '13 at 23:31

how do I test a basic javascript file with mocha?

1 Answers1