Demo that Mocha handles Promise returned from the test correctly

test.js

// It demonstrates, that instead of explicitly adding `done()` callbacks everywhere you can return Promise from method.
//
// Expected output:
// $ ./node_modules/.bin/_mocha test.js
// 
// 
//   tide retriever
//     1) should retrieve and parse tide CSV data
//     2) should retrieve and parse tide CSV data
// 
// 
//   0 passing (13ms)
//   2 failing
// 
//   1) tide retriever should retrieve and parse tide CSV data:
//      Error: Network error
//       at Object.get (test.js:5:31)
//       at Context.<anonymous> (test.js:12:23)
// 
//   2) tide retriever should retrieve and parse tide CSV data:
//      Error: Network error
//       at Object.get (test.js:5:31)
//       at Context.<anonymous> (test.js:26:30)

var should = require('should');

let tideRetriever = {
    get: () => {
        return Promise.reject(new Error("Network error"));
    }
}
let expectedCount = 3;

describe("tide retriever", function() {
    it("should retrieve and parse tide CSV data", function(done) {
        tideRetriever.get().then(
            function(entries) { // resolve
                entries.should.be.instanceof(Array).and.have.lengthOf(expectedCount);
                done(); // test passes
            },
            function(err) { // reject
                done(err); // Promise rejected
            }
        ).catch(function (err) {
            done(err); // should throwed assertion
        });
    });

    it("should retrieve and parse tide CSV data", function() {
        return tideRetriever.get().then(
            function(entries) { // resolve
                entries.should.be.instanceof(Array).and.have.lengthOf(expectedCount);
            }
        );
    });
});