如何使用Mocha对CodeEval的JS代码进行单元测试？

Question

I would like to unit test my JavaScript solution for a challenge on the CodeEval site using Mocha framework.

I could create separate files or use some other fancy approach, but:

• I want my solution to be ready to upload just after unit tests pass, without any files changes (that I could forgot to do).
• Additional code should not introduce unnecessary time or memory usage.

But CodeEval requirements and Mocha seem incompatible together, or not?

Default CodeEval stub:

var fs  = require("fs");
fs.readFileSync(process.argv[2]).toString().split('\n').forEach(function (line) {
if (line != "") {
    //do something here
    console.log(answer_line);
}

Answer 1

It's quite simple to check numbers of parameters of the program. With CodeEval it will be 3, with mocha it will be 2. Mocha execution always falls into "else" and exports the logic function.

Tested solution.

var fs  = require("fs");

module.exports = processLine;

if (process.argv.length === 3) {
    // codeeval mode
    fs.readFileSync(process.argv[2]).toString().split('\n').forEach(function (line) {
        if (line != "") {
            console.log(processLine(line));
        }
    });
}

function processLine(line) {
    return line;
}

Remarks:

• It won't work if mocha is run with parameters nor with mocha.opts file, unless there's more then 3 parameters;
• setting module.exports inside the files doesn't bother CodeEval.