TDD with TypeScript

HelloWorld.ts

export class HelloWorld {
    public sayHi(name: string): string {
        return "Hi, " + name;
    }
}

HelloWorldTest.ts

import "mocha";
import "should";

import { HelloWorld } from "../src/HelloWorld";

describe("HelloWorld", () => {

    let tested: HelloWorld;

    beforeEach(() => tested = new HelloWorld());

    describe("Say hi", () => {

        it("should say Hi, somkiat", () => {
            const result = tested.sayHi("somkiat");
            const expected = "Hi, somkiat";
            result.should.be.equal(expected);
        });

        it("should say Hi, somkiat2", () => {
            const result = tested.sayHi("somkiat2");
            const expected = "Hi, somkiat2";
            result.should.be.equal(expected);
        });

    });

});

package.json

{
  "name": "helloworld",
  "version": "1.0.0",
  "description": "TDD with TypeScript",
  "main": "index.js",
  "scripts": {
    "test": "mocha"
  },
  "devDependencies": {
    "@types/mocha": "2.2.39",
    "@types/should": "8.1.30",
    "mocha": "3.2.0",
    "should": "11.2.0",
    "typescript": "2.1.6"
  }
}

package2.json

{
  "name": "helloworld",
  "version": "1.0.0",
  "description": "TDD with TypeScript",
  "main": "index.js",
  "scripts": {
    "build": "tsc",
    "pretest": "npm run build",
    "test": "mocha dist/tests"
  }
  ...
}

tsconfig.json

{
    "compilerOptions": {
        "target": "ES6",
        "module": "commonjs",
        "noEmitOnError": true,
        "noImplicitAny": false,
        "experimentalDecorators": true,
        "sourceMap": true,
        "outDir": "dist"
    },
    "exclude": [
        "dist",
        "node_modules"
    ]
}