DonateFixture.java

public class DonateFixture {	

	private Library library;
	private Title title;
	private Member donor;
	private EmailQueue queue;
	private ArgumentCaptor<EmailAlert> alert;
	private InterestedMemberSearch search;
	
	public DonateFixture(){
		search = new InterestedMemberSearchStub(
				new String[]{
						"joepublic@mymail.io",
						"janedoe@hotfrogs.org.uk", 
						"fred@bloggs.eu"
						}
				);
	}

	public void setDonor(String memberId){
		donor = new Member();
		donateTitle();
	}
	
	public void setTitle(String name){
		title = new Title(name);
	}

	public boolean libraryContains(){
		return library.contains(title);
	}
	
	public int copyCount(){
		return title.getCopyCount();
	}
	
	public int rewardPoints(){
		return donor.getRewardPoints();
	}
	
	public String emailSubject(){
		return alert.getValue().getSubject();
	}
	
	public String emailBody(){
		return alert.getValue().getBody();
	}

	public String recipients(){
		return alert.getValue().getRecipients();
	}	
	
	@Test
	public void donateMovieThatIsntInTheLibrary(){
		setTitle("The Abyss");
		setDonor("joepeters");
		assertTrue(libraryContains());
		assertEquals(1, copyCount());
		assertEquals(10, rewardPoints());
		assertEquals("Now available - The Abyss", emailSubject());
		assertEquals("Dear member, just to let you know that The Abyss is now available to borrow",
						emailBody());
		assertEquals("joepublic@mymail.io, janedoe@hotfrogs.org.uk, fred@bloggs.eu",
						recipients());
	}
	
	private void donateTitle() {
		queue = mock(EmailQueue.class);
		alert = ArgumentCaptor.forClass(EmailAlert.class);
		library = new Library(queue, search);
		library .donate(title, donor);
		verify(queue).send(alert.capture());
	}
}

Example of a FitNesse fixture adapted to run as a JUnit test, too. Beware: order of inputs & outputs is important as to when to do set-up.

Screenshot of FitNesse Wiki page: