@Test
public void shouldDisplayFormattedTimeWhenFormattedTimeIsAnEmptyString() {
createBooksPrintStreamDateTimeAndLibrary();
when(dateTimeFormatter.print(time)).thenReturn("");
library.welcome(time);
verify(printStream).println(contains("The current time is "));
}
// This one is done for you
@Test
public void shouldWelcomeUser() {
// We don't need to mock DateTime because it is a value object
// We can't mock it because it is a final class
createBooksPrintStreamDateTimeAndLibrary();
library.welcome(time);
verify(printStream).println(contains("Welcome"));
}