function depositProfit(deposit, rate, threshold) {
    //  write code here.
    let balance = deposit * ( 1 + rate / 100 );
    let years = 1;
    
    do {        
        balance = balance * ( 1 + rate / 100 );
        ++years;
    } while( balance < threshold)
    
    return years;
    
}



/**
* Test Suite 
*/
describe('depositProfit()', () => {
    it('returns number of years it will take to hit threshold based off of deposit & rate', () => {
        // arrange
        const deposit = 100;
        const rate = 20;
        const threshold = 170;
        
        // act
        const result = depositProfit(deposit, rate, threshold)

        // log
        console.log("result: ", result);
        
        // assert
        expect(result).toBe(3);
    });
});