/zad2.js/

class Calculator {
  constructor(first_number, second_number, operation) {
    this.first_number = first_number;
    this.second_number = second_number;
    this.operation = operation;
  }

  calculate(operation) {
    var res;
    this.operation = operation;
    if (this.operation === "+") {
      res = this.first_number + this.second_number;
      console.log("Addition: " + res);
      return res;
    } else if (this.operation === "-") {
      res = this.first_number - this.second_number;
      console.log("Subtraction: " + res);
      return res;
    } else if (this.operation === "*") {
      res = this.first_number * this.second_number;
      console.log("Multiplication: " + res);
      return res;
    } else if (this.operation === "/") {
      if (this.second_number === 0) {
        throw new Error("Cannot divide by zero");
      }
      res = this.first_number / this.second_number;
      console.log("Division: " + res);
      return res;
    } else {
      throw new Error("Incorrect operation");
    }
  }
}
module.exports = Calculator;


/zad2.test.js/

const assert = require("chai").assert;

const Calculator = require("./../zad2");

let first_number = 10;
let second_number = 50;
let operation = "+";
let testApp = new Calculator(first_number, second_number, operation);

describe("Calculator testing", function() {
  it("varijable first_number i second_number moraju biti numeričkog tipa  ", function() {
    assert.isNumber(testApp.first_number);
    assert.isNumber(testApp.second_number);
    /*assert.isNumber(testApp.calculate(-5, -2, "+"));
    assert.isNumber(testApp.calculate(-5, -2, "-"));
    assert.isNumber(testApp.calculate(-5, -2, "*"));
    assert.isNumber(testApp.calculate(-5, 2, "/"));*/
  });
  /*
  it("Metoda calculate mora primati podatke numeričkog tipa ", function() {
    assert.throws(() => {
      testApp.calculate("+");
    }, Error);
  });*/

  it("Operacije koje se mogu izvršiti su: +,-,*,/", function() {
    var Obj1 = ["+", "-", "/", "*"];
    assert.include(Obj1, testApp.operation);
  });

  it("Rezultat kalkulacije mora biti broj", function() {
    assert.isNumber(testApp.calculate("*"));
  });
});
/*
  it("powerStatus mora biti boolean", function() {
    assert.isBoolean(testApp.powerStatus);
  });

  it("metode za paljenje i gašenje stroja moraju vratiti status Boolean tipa", function() {
    assert.isBoolean(testApp.turnMachineOn());
    assert.isBoolean(testApp.turnMachineOff());
  });

  it("Metoda refill mora primati parametre numerickog tipa ", function() {
    assert.throws(() => {
      testApp.refill("kava", "voda");
    }, Error);
  });
});
*/