Writing functions and Tests

catFacts.js

const axios = require('axios');

async function catFacts() {
  try {
    const response = await axios({
      method: "get",
      status: 200,
      url: "https://cat-fact.herokuapp.com/facts/random?animal_type=cat&amount=3"
    });
    let extracts = response.data;
    console.log(`\nBelow are some few random cat facts: \n=============================`);
    extracts.forEach(element => {
      console.log(`\t ${element.text}\n`)      
    });    
  } catch (error) {
    let errResponse = {
      status: 503,
      message: `${error} occured, while trying to connect to the server`
    }
    return (errResponse);
  }
};
module.exports = catFacts;
// console.log(catFacts());

catFacts.test.js

const axios = require("axios");
const getCatFacts = require("../catFacts");

jest.mock('axios');

test('should some facts about cats', () => {
  const facts = [
    {fact: "The Bombay cat breed was developed to resemble a miniature panther"},
    {fact: "Every year, nearly four million cats are eaten in China as a delicacy"},
    {fact: "Cats respond better to women than to men, probably due to the fact that women's voices have a higher pitch"}
  ];
  const resp = {data: facts};
  
  axios.get.mockImplementation(() => Promise.resolve(resp))

  return getCatFacts().then(resp => expect(resp.data).toEqual(facts));
});

emailGenerator.js

function emailGenerator (firstname, lastname){
  let first = String(firstname);
  let last = String(lastname);
  let letters = /^[A-Za-z]+$/;

  if(first.match(letters) && last.match(letters)){
    return (`${firstname.toLowerCase()}.${lastname.toLowerCase()}@mailer.com`);
  }
  return (`Your Firstname and Lastname should contain only letters`);
}
module.exports = emailGenerator;

emailGenerator.test.js

const mailGen = require("../emailGenerator");

test('uses firstname and lastname to generate email', () => {
  expect(mailGen("Mike", "Edward")).toBe("mike.edward@mailer.com");
});

multiplyList.js

function intArray (intList){
  if(!Array.isArray(intList) || intList.length > 0){

    let multiList = [];

    for(let i = 0; i < intList.length; i++){
      if(isNaN(parseInt(intList[i]))){
        return `Array of integers only allowed`;
      }
      multiList.push(intList[i] * 2);

    }
    return multiList;
  }else{
    return `Entry must be an Array and must not be empty`;
  }
};

module.exports = intArray;

// console.log(intArray([2,3,0,9]));

multiplyList.test.js

const multiList = require("../intArray");

test("Multiplies all the item in a number array by 2", () => {
  expect(multiList([1])).toEqual([2]);
});