text: import calculateTotalInterest from './calculateTotalInterest';
  
  describe('calculateTotalInterest', () => {
    it('correctly handle empty values', () => {
      expect(calculateTotalInterest({
        notional: 0,
        interestRate: 10,
        interestPeriod: 1,
        loanDuration: 2,
      })).toBe(0);
  
      expect(calculateTotalInterest({
        notional: 1000,
        interestRate: 0,
        interestPeriod: 1,
        loanDuration: 2,
      })).toBe(0);
  
      expect(calculateTotalInterest({
        notional: 1000,
        interestRate: 10,
        interestPeriod: 0,
        loanDuration: 2,
      })).toBe(0);
  
      expect(calculateTotalInterest({
        notional: 1000,
        interestRate: 10,
        interestPeriod: 1,
        loanDuration: 0,
      })).toBe(0);
  
      expect(calculateTotalInterest({
        notional: 0,
        interestRate: 0,
        interestPeriod: 0,
        loanDuration: 0,
      })).toBe(0);
  
      expect(calculateTotalInterest({
        notional: null,
      })).toBe(0);
    });
  
    it('correctly calculate total interest', () => {
      expect(calculateTotalInterest({
        notional: 1000,
        interestRate: 10,
        interestPeriod: 1,
        loanDuration: 2,
      })).toBe(200);
  
      expect(calculateTotalInterest({
        notional: 500,
        interestRate: 10,
        interestPeriod: 12,
        loanDuration: 30,
      })).toBe(125);
    });
  
    it('will return decimal value', () => {
      expect(calculateTotalInterest({
        notional: 100,
        interestRate: 1,
        interestPeriod: 10,
        loanDuration: 15,
      })).toBe(1.5);
  
      expect(calculateTotalInterest({
        notional: 100,
        interestRate: 1,
        interestPeriod: 100,
        loanDuration: 75,
      })).toBe(0.75);
    });
  });
  