edurne.js

function getOrStoreTeam(db, teamId, teamName) {
  return db
    .getTeam(teamId)
    .then((team) => {
      if (team === undefined) {
        return db.saveTeam(teamId, teamName);
      }
      return team;
    });
}

function startGame(db, homeTeam, awayTeam) {
  const homePromise = getOrStoreTeam(db, homeTeam.id, homeTeam.name);
  const awayPromise = getOrStoreTeam(db, awayTeam.id, awayTeam.name);
  return Promise.all([homePromise, awayPromise]);
}

module.exports = {
  getOrStoreTeam,
  startGame,
};

package.json

{
  "name": "ti",
  "version": "1.0.0",
  "description": "",
  "main": "erica.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "chai": "^4.0.1",
    "eslint": "^3.19.0",
    "eslint-config-airbnb": "^15.0.1",
    "eslint-plugin-import": "^2.3.0",
    "eslint-plugin-jsx-a11y": "^5.0.3",
    "eslint-plugin-react": "^7.0.1",
    "mocha": "^3.4.2"
  }
}

test.js

const expect = require('chai').expect;
const {getOrStoreTeam, startGame} = require('./edurne.js');

describe('#getOrStoreTeam(teamName, teamId)', () =>{
  it('gets a team from the database', (done) => {
    const dodgers = {id: 1, name: 'Dodgers'};
    const teams = [dodgers]
    const db = {
      getTeam(teamId){
        return Promise.resolve(teams.find(team => team.id === teamId));
      }
    }
    getOrStoreTeam(db, 1, 'Dodgers').then((team) => {
      expect(team).to.eq(dodgers);
      done();
    })
  });
  it('saves the team to the database if not found', (done) => {
    const dodgers = {id: 1, name: 'Dodgers'};
    const teams = [dodgers]
    const db = {
      getTeam(teamId){
        return Promise.resolve(teams.find(team => team.id === teamId));
      },
      saveTeam(teamId, teamName){
        const createdTeam = {id: teamId, name: teamName};
        teams.push(createdTeam);
        return Promise.resolve(createdTeam);
      }
    }

    getOrStoreTeam(db, 2, "Lakers")
      .then((team) => {
        expect(team).to.deep.eq({id: 2, name: "Lakers"});
        expect(teams).to.deep.include({id: 2, name: "Lakers"});
        done();
      })
  });
});

describe('#startGame(homeTeam, awayTeam)', () => {
  it('creates or gets the teams as needed', (done) => {
    const dodgers = {id: 1, name: 'Dodgers'};
    const lakers = {id: 2, name: 'Lakers'};
    const teams = [dodgers]
    const db = {
      getTeam(teamId){
        return Promise.resolve(teams.find(team => team.id === teamId));
      },
      saveTeam(teamId, teamName){
        const createdTeam = {id: teamId, name: teamName};
        teams.push(createdTeam);
        return Promise.resolve(createdTeam);
      }
    }

    startGame(db, dodgers, lakers)
      .then(([home, away]) => {
        expect(home).to.deep.eq(dodgers);
        expect(away).to.deep.eq(lakers);
        expect(teams).to.deep.include(lakers);
        done();
      });

  })
});