Why do you write unit test? To verify your code does the right thing? Ok, that’s a fair usage of the unit test. But you can do much more with it.

1. STOP TESTING – START
DESIGNING
Transform your Unit
Testing practice

2. HOW DO YOU
DESIGN WITH
UNIT TEST ?
https://www.flickr.com/photos/through-rimas-

3. WHAT DOES IT MEAN TO DESIGN ?
………………… goal ……………………………………..
……………… object ……………………………………...
…requirements ………… and constraints …………………
……………………………………………………………...
……………………………………..environment…………..
……………………………………………………………...
…aesthetic………………………………………………….
…………………………………..functional……………….

4. AGENDA
 Design Tools : CRC Cards
 Testing Tool : Code coverge
 Documentation Tool : Sequence
diagram
 A few Tips

5. CRC CARDS
https://www.flickr.com/photos/teamaskins/

6. Class
Responsibilities
•
•
•
Collaborato
rs
•
•

7. Shipment
Responsibilities:
• Records Date
• Verify
Availability
• Trigger
invoices
Collaborato
rs:
• Stock
• Accounti
ng

8. public class XxxxxxxTest {
}

9. public class ShipmentTest {
Shipment shipment = new Shipment();
}
Class

10. public class ShipmentTest {
@Mock Stock stock;
@Mock Accounting accountant;
Shipment shipment = new Shipment(stock, accountant);
}
Collaborator
s
Class

11. public class ShipmentTest {
@Mock Stock stock;
@Mock Accounting accountant;
Shipment shipment = new Shipment(stock, accountant);
@Test void testRecordsDate() {
…
}
@Test void testVerifyAvailability() {
…
}
@Test void testTriggerInvoice() {
…
}
}
Collaborator
s
Class
Responsibilit
ies

12. THINK ABOUT RESPONSIBILITIES
https://www.flickr.com/photos/70554893@N00/

13. CODE COVERAGE – A DESIGN TOOL
https://www.tasktop.com/blog/incremental-code-coverage-
Responsibilities :
• Zoom
• Adjust to metric
• Adjust to large
scale

14. Choice =>
Responsibility
https://www.flickr.com/photos/dheeranet/

15. RESPONSIBILITY
TESTING
SCENARIO BASED TESTING
https://www.flickr.com/photos/dh

16. @Test(expect=UnavailableProduct.class)
public void testVerifyAvailability() {
Order order = aSampleOrder().unavailable();
expect(stock).isAvailable(); will(returnValue(false));
shipment.ship(order)
}
@Test(expect=UnavailableProduct.class)
public void testShipUnavailableOrder() {
Order order = aSampleOrder().unavailable();
expect(stock).isAvailable(); will(returnValue(false));
shipment.ship(order)
}
Responsibili
ty
Scenario

17. SEQUENCE /
COLLABORAT
ION
DIAGRAM
https://www.flickr.com/photos/12665453

18. UN SEQUENCE
Caller prepare order
Collaborators : Stock, accounting
call ship(order)
Shipment call stock.isAvailable() [Expectation]
Shipment call accounting.sendInvoice [Expectation]
My sequence diagram is a test …. My test is a sequence diagram…
Stock stock = mock(Stock.class);
Accounting acc = mock(Accounting.class);
Shipping shipment = new Shipping(stock,acc);
public void testShipOrder() {
shipment.ship(order);
verify(stock).isAvailable(order);
verify(acc).sendInvoice(order);
}

19. TEST IS A
DOCUMENTAT
ION

20. THE CODE MUST WORK
NOW
AND LATER
Developer
responsibility
https://www.flickr.com/photos/joans
orolla/

21. WHAT DOES IT MEAN TO DESIGN ?
………………… goal ……………………………………..
……………… object ……………………………………...
…requirements ………… and constraints …………………
……………………………………………………………...
……………………………………..environment…………..
……………………………………………………………...
…aesthetic………………………………………………….
…………………………………..functional……………….

22. DESIGN -
AESTHETIC
Use Refactring
• Keep functional aspects
• Keep your design choice
unchanged
• Foccus on aesthetic
https://www.flickr.com/photos/59810064
@N07/

23. DESIGN - ENVIRONMENT
Object is designed
for an environment
Unit test is a
documentation of
that environment
https://www.flickr.com/photos/dms
umon/

24. UNIT TESTING TIPS
https://www.flickr.com/photos/phalene

25. NO NOISE Unit test is a
documentation
https://www.flickr.com/photos/dalbera
/

26. NO NOISE – PRIVATE IS USELESS
public class ShipmentTest {
@Mock private Stock stock;
@Mock private Accounting accountant;
private Shipment shipment = new Shipment(stock, accountant);
…
}

27. NO NOISE – PRIVATE IS USELESS
public class ShipmentTest {
@Mock private Stock stock;
@Mock private Accounting accountant;
private Shipment shipment = new Shipment(stock, accountant);
…
}

28. NO NOISE – PRIVATE IS USELESS
public class ShipmentTest {
@Mock Stock stock;
@Mock Accounting accountant;
Shipment shipment = new Shipment(stock, accountant);
…
}

29. NO NOISE – LIGHT SETUP
public class ShipmentTest {
Stock stock;
Accounting accountant;
Shipment shipment;
@Before
public setUp() {
stock = mock(Stock.class);
accountant = mock(Accounting.class);
shipment = new Shipment(stock, accountant);
}
}

30. NO NOISE – LIGHT SETUP
public class ShipmentTest {
Stock stock = mock(Stock.class);
Accounter accounter = mock(Accounter.class);
Shipment shipment = new Shipment(stock, accounter);
@Before
public setUp() {
stock = mock(Stock.class);
accounter = mock(Accounter.class);
shipment = new Shipment(stock, accounter);
}
}

31. NO NOISE – LIGHT SETUP
public class ShipmentTest {
Stock stock = mock(Stock.class);
Accounter accounter = mock(Accounter.class);
Shipment shipment = new Shipment(stock, accounter);
}

32. Unit Test is
a Design
Description
https://www.flickr.com/photos/summe

33. NO NOISE – LIGHT SETUP
public class ShipmentTest {
@Before
public setUp() {
createOrderFile();
}
}

34. NO NOISE – LIGHT SETUP
public class ShipmentTest {
@Before
public setUp() {
createOrderFile();
}
}

35. NO NOISE – LIGHT SETUP
public class ShipmentTest {
{ createOrderFile(); }
}

36. NO NOISE – LIGHT LIST SETUP
public class ShipmentTest {
List products = new LinkedList();
{
products.add(FOO);
products.add(BAR);
}
}

37. NO NOISE – LIGHT LIST SETUP
public class ShipmentTest {
List products = new LinkedList();
{{
products.add(FOO);
products.add(BAR);
}};
}

38. NO NOISE – LIGHT LIST SETUP
public class ShipmentTest {
List products = new LinkedList() {{add(FOO); add(BAR);}};
}

39. CREATE DATA
https://www.flickr.com/photos/pictures-
of-money/

40. Contract contract = aContract().createdIn(2010).at(BRUXELLES);
Contract contract = aContract().covering(
aHouse().with(aGarage(), aCellar())
).value();
CREATE DATA – BUILDER METHODS

41. COMMUNICATE
• Clear message
• No noise
• Foccus on your design
https://www.flickr.com/photos/50228879

42. CONCLUSION
Think about Responsibilities
Think to Unit test as a Documentation
You are responsible for your
code,
now,
and later…

43. @gscokart
https://www.linkedin.com/in/gsc
okart