One liner test

gistfile1.txt

TEST

public class DownloadStuffInteractorTest extends UnitTest {

	private static final String ANY_URL = "http://www.wherever.com";
	private static final String ANY_FILE_NAME = "file.pdf";
	private static final EmailWithStuff EMAIL = new EmailWithStuff(ANY_URL, ANY_FILE_NAME);

	@Mock
	private StuffDownloader StuffDownloader;

	private DownloadStuffInteractor DownloadStuffInteractor;

	@Before
	public void setup() {
		DownloadStuffInteractor = new DownloadStuffInteractor(StuffDownloader);
	}

	@Test
	public void shouldDownloadFileSilently() {
		DownloadStuffInteractor.execute(EMAIL);

		verify(StuffDownloader).silentlyDownloadFile(ANY_URL, ANY_FILE_NAME);
	}
}


SUT

public DownloadInvoiceInteractor(InvoiceDownloader invoiceDownloader) {
	this.invoiceDownloader = invoiceDownloader;
}

public void execute(EmailWithAttachment emailWithAttachment) {
	invoiceDownloader.downloadFileSilently(emailWithAttachment.getUrl(), emailWithAttachment.getFileName());
}