@Test public void testGivenTwoNumbersWhenMultiplicationThenProduct() { assertEquals(16, calculator.product(4, 4)); assertEquals(64, calculator.product(8, 8)); }
public int product(final int multiplicand, final int multiplicier) { return multiplicand * multiplicier; }
Calculator { public int product(final int multiplicand, final int multiplicier) { return multiplicand * multiplicier; } }
Calculator { public int product(final int multiplicand, final int multiplicier) { return multiplicand * multiplicier; }  }
Calculator { public int product(final int multiplicand, final int multiplicier) { return multiplicand * multiplicier; }  int sum(final int augend, final int addend); int product(final int multiplicand, final int multiplicier); }
Calculator { public int product(final int multiplicand, final int multiplicier) { return multiplicand * multiplicier; }  int sum(final int augend, final int addend); int product(final int multiplicand, final int multiplicier);  }