Cannot get report for non-covered parts of conditions

[ozum]

Hi,

I use mocha & istanbul for some projects and lab for some others.

For the very simplified example below istanbul reported 100% coverage whereas lab reported less than 100%.

Istanbul

$ istanbul cover _mocha

const Code    = require('code');
const expect  = Code.expect;

const util = require('../util');

describe('deneme', () => {
  it('should return true', (done) => {
    expect(util.deneme('a')).to.true();
    done();
  });

  it('should return false', (done) => {
    expect(util.deneme()).to.false();
    done();
  });
});

Lab

$ lab --coverage --reporter html > report.html

const Lab  = require('lab');
const Code = require('code');

const lab      = Lab.script();
const describe = lab.describe;
const it       = lab.it;
const expect   = Code.expect;

const util = require('../util');

exports.lab = lab;
describe('deneme', () => {
  it('should return true', (done) => {
    expect(util.deneme('a')).to.true();
    done();
  });

  it('should return false', (done) => {
    expect(util.deneme('b')).to.false();
    done();
  });
});

Function

// util.js file
function deneme(a) {
  return (a && a.startsWith('a')) ? true : false;
}

module.exports = {
  deneme
};

Although two branches are executed by tests and as a result tests seem to cover 100% of the code, second part of the condition is never tested/executed.

lab reported that first part of the condition a is always true, so that second part a.startWith('a') is never executed. Please see screenshot below:

A third test should be added for this case:

  it('should return false for undefined', (done) => {
    expect(util.deneme()).to.false();
    done();
  });

Not in this simple example, but in more complex situations it helped me hunt some hard to catch bugs.

Is it possible to detect condition coverage in Istanbul?

Kind Regards,

[ozum]

I got confused, but I see that project continues under another repo. I moved my question to https://github.com/istanbuljs/nyc/issues/538.