Testing Dates

entry.Journal adjusts its lastEntryDateTime if the most recent existing entry is removed. It would be a good idea to make sure that the dates actually change, but I'm pretty sure the current interface does not support any custom Clocks or times. I could add functionality to allow times to be set relative to a different Clock for the sake of testability, but perhaps it would be best if this was possible without exposing the inner workings of the class. It could be part of the Journal constructor?

I think I have some tests about creating objects that are/use EntryDateTime and make sure that the returned date is the same. For example, in EntryDateTimeTest we have

private EntryDateTime entryDateTime;
// ...
@Test
public void testNow() {
    entryDateTime = EntryDateTime.now();
    testDate = ZonedDateTime.now().toLocalDate();
    assertEquals(formatShort(testDate), entryDateTime.dateShort());
}

This is pretty much just duplicating the implementation of EntryDateTime.

In JournalTest,

@Test
public void testAddEntry() {
    EntryDateTime dateTimeNow = EntryDateTime.now();
    Entry entry = new Entry("This is the description");
    journal.add(entry);

    assertEquals(1, journal.size());

    try {
        assertEquals(dateTimeNow.dateShort(), journal.lastEntryDateShort());
    } catch (NoEntriesAddedException e) {
        fail("caught " + e.toString() + " when unexpected");
    }
    // ...
}

This is creating a date, dateTimeNow, and comparing it with the entry to make sure they have the same date. This code assumes that both lines will be executed at exactly the same time. In reality, they are probably some small amount of time off which might cause this test to fail in certain circumstances. This approach will not scale to testing anything with seconds or minutes.

Resources

• https://www.baeldung.com/java-override-system-time