Solución al problema de efectuar operaciones (solamente suma en este caso) entre dos tipos de monedas, haciendo uso de Javascript y Jasmine. La clase MoneyCalculator contiene el metodo *sum* que permiten operar entre dos objetos, cuyas propiedades son *monto* y *moneda*. La clase MoneyCalculator recibe como parametro un objeto *exchangeService* …

MoneyCalculator.js

var MoneyCalculator = function (exchangeService) {

    this.sum = function (a, b) {
        if (a.currency !== b.currency) {
            b.amount = exchangeService.convert(b, a.currency);
        }
        return {
            "amount" : a.amount + b.amount,
            "currency" : a.currency
        };
    };

};

MoneyCalculatorSpec.js

describe("Sum of money", function() {

    var moneyCalculator;
    var firstParam;
    var exchangeServiceFake;

    beforeEach(function() {
        exchangeServiceFake = jasmine.createSpyObj('exchangeService',['convert']);
        moneyCalculator = new MoneyCalculator(exchangeServiceFake);
        firstParam = {"amount": 200, "currency": "CLP"};
    });
    describe("Given 200 CLP and ", function() {
        it("100 CLP, should be 300 CLP", function() {
            var secondParam = {"amount": 100, "currency": "CLP"};
            var result = moneyCalculator.sum(firstParam, secondParam);
            var expected = {"amount": 300, "currency": "CLP"};
            expect(expected).toEqual(result);
        });
        it("100.50 CLP, should be 300.50 CLP", function() {
            var secondParam = {"amount": 100.50, "currency": "CLP"};
            var result = moneyCalculator.sum(firstParam, secondParam);
            var expected = {"amount": 300.50, "currency": "CLP"};
            expect(expected).toEqual(result);
        });
        it("-100 CLP, should be 100 CLP", function() {
            var secondParam = {"amount": -100, "currency": "CLP"};
            var result = moneyCalculator.sum(firstParam, secondParam);
            var expected = {"amount": 100, "currency": "CLP"};
            expect(expected).toEqual(result);
        });
        it("0 CLP, should be 200 CLP", function() {
            var secondParam = {"amount": 0, "currency": "CLP"};
            var result = moneyCalculator.sum(firstParam, secondParam);
            var expected = {"amount": 200, "currency": "CLP"};
            expect(expected).toEqual(result);
        });
        it("10 CHF, should be  300 CLP", function() {
            exchangeServiceFake.convert.andCallFake(function() {
                return 100;
            });

            var secondParam = {"amount": 10, "currency": "CHF"};
            var result = moneyCalculator.sum(firstParam, secondParam);
            var expected = {"amount": 300, "currency": "CLP"};
            expect(expected).toEqual(result);
            expect(exchangeServiceFake.convert).toHaveBeenCalled();
            expect(exchangeServiceFake.convert).toHaveBeenCalledWith(secondParam, "CLP");
        });
    });
});