### Question:
DayOfMonthMatcher extends FeatureMatcher<DateTime, Integer> { public static Matcher<DateTime> onDayOfMonth(Matcher<Integer> dayMatcher) { return new DayOfMonthMatcher(dayMatcher); } DayOfMonthMatcher(Matcher<Integer> subMatcher); static Matcher<DateTime> onDayOfMonth(Matcher<Integer> dayMatcher); static Matcher<DateTime> onDayOfMonth(Integer... days);  }### Answer:
@Test public void test() throws Exception { assertThat(onDayOfMonth(10), AllOf.<Matcher<DateTime>>allOf( matches(DateTime.parse("20180710T010001Z")), mismatches(DateTime.parse("20181001T005959Z"), "day of month was <1>"), mismatches(DateTime.parse("20181011T010000Z"), "day of month was <11>"), describesAs("day of month (<10>)") )); assertThat(onDayOfMonth(6, 8, 10), AllOf.<Matcher<DateTime>>allOf( matches(DateTime.parse("20180706T010001Z")), matches(DateTime.parse("20180708T010002Z")), matches(DateTime.parse("20180710T010003Z")), mismatches(DateTime.parse("20180605T005959Z"), "day of month was <5>"), mismatches(DateTime.parse("20180811T005958Z"), "day of month was <11>"), mismatches(DateTime.parse("20181009T005957Z"), "day of month was <9>"), mismatches(DateTime.parse("20180907T010000Z"), "day of month was <7>"), describesAs("day of month (<6> or <8> or <10>)") )); }