Using TypeScript, Mocha, and Chai without Modules

Question

I'm using TypeScript and trying to do so without creating any modules (ie no export statements). Using modules would require using SystemJS or AMD and I'm trying to keep my project as simple as possible.

I'd like to create unit tests, and it seems like Mocha/Chai is the most popular way to do that.

I have 3 files:

// ../src/Cell.ts
class Cell {
    public Z: number;
    public Y: number;
    public X: number;

    constructor (z: number, y: number, x: number) {
        this.Z = z;
        this.Y = y;
        this.X = x;
    }
}

// ../src/Maze.ts
class Maze {
    public myCell: Cell;
    private width: number;

    constructor (width: number) {
        this.myCell = new Cell(-1, -1, -1);
    }

    protected directionModifier(cell: Cell, direction: string) {
        // does something
    }
}

// ../test/MazeTests.ts
let chai = require('chai');
import { expect } from 'chai';
var assert = require('assert');
var mocha = new Mocha();
mocha.addFile('../src/Cell.ts');
mocha.addFile('../src/Maze.ts');

describe('Maze Test Suite', function ()  {

    it('should return a cell x-1 of the current location (1 cell to the south)', function () {

        let myMaze = new Maze(4);
        let myCell = new Cell(0,0,0);

        const result =  myMaze.directionModifier(myCell,"South");

        assert.deepEqual(result, new Cell(0,1,0));

    });
});

I get a few errors when I run npm test :

test/MazeTests.ts(42,20): error TS2304: Cannot find name 'Maze'.
test/MazeTests.ts(43,20): error TS2304: Cannot find name 'Cell'.
test/MazeTests.ts(47,38): error TS2304: Cannot find name 'Cell'.

There's a distinct possibility I'm missing something obvious.

Answer 1

Cell and Maze variables are not defined anywhere in the your test file. You cant do new Maze and new Cell because they dont exist.

Ive never heard of loading a class from another file without it being exported and i dont know what mocha.addFile does, since i prefer Jasmine over Mocha and Chai...especially for Typescript projects.

If, however, the line mocha.addFile creates an output variable with the contents of whatever is defined in the file, try defining those as Maze and Cell. Then create the objects.

However, the best aproach would be to do export on both Cell and Maze classes and import them in the test file.

Answer 2

In case this is useful to anyone else, I figured out a hacky workaround:

I installed and modified concat:

npm install concat

// in concat/index.js
// change lines 25-26 so that the `read` function is:
const read = (fName) => new Promise((res, rej) => {
    fs_1.readFile(path_1.resolve(fName), (err, str) => {
        if (err)
            rej(err);
        var newText = str.toString().replace(/^class /g, 'export class ')
        res(newText)
    });
});

// in the test file:
// first run: comment out the later lines
// next run: use whole document
import { expect } from 'chai';
import 'mocha';
var concat = require('concat')
var assert = require('assert');
concat([
    "./src/Cell.ts",
    "./src/Character.ts",
    "./src/Maze.ts",
    "./src/MazeView.ts",
    "./src/main.ts"], './test/testable.ts');

import { Cell } from '../test/testable';
import { Maze } from '../test/testable';


describe('Maze Test Suite', function () {

    it('should return a cell x-1 of the current location (1 cell to the south)', function () {

        let InstanceOfMaze = new Maze(4, 8, 8);

        const result = InstanceOfMaze.directionModifier(new Cell(0, 0, 0), "South");
        assert.deepEqual(result, new Cell(0, 1, 0));

    });
});