LeapYear { public boolean isLeap(int year) { if (isDivisibleBy(year, 400)) { return true; } return isDivisibleBy(year, 4) && !isDivisibleBy(year, 100); }  boolean isLeap(int year);  }
@Test public void testIsLeap() { assertThat(leapYear.isLeap(year)).isEqualTo(isLeapYear); }