tavon.org

To-Do List

$5 + 10 CHF = $10 if rate is 2:1
$5 * 2 - $10
Make "amount" private
Dollar side effects?
Money rounding?
equals()
hashCode()
Equal null
Equal object
5 CHF * 2 - 10 CHF
Dollar/Franc duplication
Common equals
Common times
Compare Francs with Dollars
Currency?

To-Do List

$5 + 10 CHF = $10 if rate is 2:1
$5 * 2 - $10
Make "amount" private
Dollar side effects?
Money rounding?
equals()
hashCode()
Equal null
Equal object
5 CHF * 2 - 10 CHF
Dollar/Franc duplication
Common equals
Common times
Compare Francs with Dollars

To-Do List

$5 + 10 CHF = $10 if rate is 2:1
$5 * 2 - $10
Make "amount" private
Dollar side effects?
Money rounding?
equals()
hashCode()
Equal null
Equal object
5 CHF * 2 - 10 CHF
Dollar/Franc duplication
Common equals
Common times

Test Code

public void testMultiplication {
  Dollar five = new Dollar(5);
  assertEquals(new Dollar(10), five.times(2));
  assertEquals(new Dollar(15), five.times(3));
}

To-Do List

$5 + 10 CHF = $10 if rate is 2:1
$5 * 2 - $10
Make "amount" private
Dollar side effects?
Money rounding?
equals()
hashCode()
Equal null
Equal object

Test Code

public void testMultiplication {
  Dollar five = new Dollar(5);
  assertEquals(new Dollar(10), five.times(2));
  assertEquals(new Dollar(15), five.times(3));
}

To-Do List

$5 + 10 CHF = $10 if rate is 2:1
$5 * 2 - $10
Make "amount" private
Dollar side effects?
Money rounding?
equals()
hashCode()

public void testEquality() {
  assertTrue(new Dollar(5).equals(new Dollar(5)));
}

TDD Cycle

1. Write a test
2. Make it run
3. Make it right

The goal is clean code that works - Ron Jeffries

So we want to test multiplication and make sure that the "times()" method returns the right amount when passed a multiplier.

public void testMultiplication() {
  Dollar five = new Dollar(5);
  Dollar product = five.times(2);
  assertEquals(10, product.amount);
  product = five.times(3);
  assertEquals(15, product.amount);
}