Testing is a part of software engineering process. You wouldn't promote a code you haven't tested to production, so why don't you use automated testing and actually reduce costs and increase the efficiency? You can also learn how doing testing can put pressure on your code to improve your architecture.

1. Saul Diaz
Android Lead @ Fever Inc.
@sefford
sefford@gmail.com
DAT TESTING

3. "Welcome to the Enrichment Center!"
Why

4. Testing is about...

5. Testing is about...
Ctrl

6. Testing is about...

7. “At the end of the experiment you will be baked and then there will be…
cake.”
Basics

8. Setup
Exercise
Verify
Teardown

9. SUT
BLACK
BOX
WHITE
BOX

10. public class SaiyanSagaTest {
public static final int GOKU_POWER_LEVEL = 10000;
public static final String EXPECTED_GOKU_OUTCOME ="It's over nine thousaaaaaaaaand!";
// public Saiyan(KiiSensingInterface sensingMethod)
Saiyan goku, vegeta, nappa;
@Before
public void setUp() {
// KiSense and Scouter classes implement KiSensingInterface
goku = new Saiyan(new KiSense());
nappa = new Saiyan(null);
vegeta = new Saiyan(new Scouter());
}
@Test
public void testVegetaReadsGokusPowerLevel() throws Exception {
goku.setPowerLevel(GOKU_POWER_LEVEL);
assertThat(EXPECTED_GOKU_OUTCOME, vegeta.scanPowerLevel(goku));
}
@After
public void tearDown() {
nappa.finish();
}
}

11. STU
B
MOCK

12. Code Unit
Integratio
n
Acceptanc
e

13. “All Aperture technologies remain operational up to 4.000ºK.”
Efficiency

14. DETERMINISTI
C
FAS
T
EAS
Y

16. public class Tard {
// Initialize rest of Tard, it was awful
public String getResponse() {
return “nope”;
}
}
public class TardTest {
Tard tard = new Tard();
// Look ma’, I’m testing stuff
@Test
public void testGetTardResponse() throws Exception {
assertEquals(EXPECTED_NOPE, tard.getResponse());
}
}

17. public class Fry{
public void shutUpAndTakeMy(Money money) {
if (money != null)
shutUpAndTakeIt(money);
}
}
public class FuturamaTest {
@Mock Account fryAccount;
@Mock BankFactory bank;
@Spy Fry fry;
// I don’t want to live with this testing anymore
@Test
public void testIDontHaveAnyMoneyToTake() throws Exception {
when(fryAccount.getMoney()).thenReturn(null);
verify(fry, never()).shutUpAndTakeIt(fryAccount.getMoney());
}
}

18. public class Snape {
public int pointsToGryffindor(Student student) {
if (Student.DANIEL_RADCLIFFE.equalsTo(student))
return -10;
else if (Student.EMMA_WATSON.equalsTo(student))
return Integer.MAX_INT;
return 10;
}
}
public class HogwartsTest {
public static int MAX_POINTS = Integer.MAX_INT;
@Spy
Snape snape;
// Bullshit! 2,147,483,647 points to Gryffindor!
@Test
public void testSnapeGivingPointsToHermione() throws Exception {
when(snape.pointsToGryffindor(((Student) any()))).thenReturn(MAX_POINTS);
assertEquals(MAX_POINTS, snape.pointsToGryffindor(Student.EMMA_WATSON));
}
}

19. “Sorry fellas. She’s married. To science.”
Technology

20. MOCKING & STUBBING UNIT & INTEGRATION ACCEPTANCE
Mockito JUnit Espresso
JMock Robolectric Robotium
PowerMock Calabash
Additionally JaCoCo can help you on keeping an eye on code coverage.

21. “Spaaaaaaaaaaaaaaaaaaaace!”
F*** tips!

22. UNIT F***S EVERYTHING
ELSE*
*Except singletons, UI & race conditions. Those f***ers cannot be tested.

24. *
* Speak F***ing English too.

26. public class MarceusWallace {
public void initialization(){
// Lots of stuff concerning intialization
this.looksLikeABitch = !(Locale.WHAT.equalTo(this.brett.getLocale()) &&
Locale.ENGLISH.getDisplayLanguage().equalTo(
this.brett.getLocale().getDisplayLanguage()) &&
this.jules.describeMarceusWallace(this.brett) &&
this.brett.getWhatCounter() < 7);
}
}
public class MarceusWallaceTest {
@Test
public void testMrWallaceDoesNotLookLikeABitch() throws Exception {
// Testing all cases would lead to 24 cases plus every branch of the method
when(brett.getLocale()).thenReturn(whatLocale);
when(brett.getWhatCounter).thenReturn(5);
when(whatLocale.getDisplayLanguage())
.thenReturn(Locale.ENGLISH.getDisplayLanguage());
when(jules.describeMarceusWallace(brett)).thenReturn(Boolean.TRUE);
controller.initialize();
assertFalse(controller.doesLookLikeABitch());
}
}

27. public class MarceusWallace {
public void initialization(){
// Nice refactor!
this.looksLikeABitch = calculateIsLookingLikeABitch();
}
}
public class MarceusWallaceControllerTest {
@Test
public void testMrWallaceDoesNotLookLikeABitch() throws Exception {
// Much better! But what if Jules and Brett are final or cannot be mocked
// that would be still a lot of boilerplate!
when(controller.calculateIsLookingLikeABitch()
.thenReturn(Boolean.FALSE);
controller.initialize();
assertFalse(controller.doesLookLikeABitch());
}
}

28. public class MarceusWallace {
public void initialization(){
// Now I can test calculateIsLooking injecting its dependencies!
this.looksLikeABitch = calculateIsLookingLikeABitch(this.brett, this.jules);
}
}
public class MarceusWallaceControllerTest {
@Test
public void testMrWallaceDoesNotLookLikeABitch() throws Exception {
// Using a spy and injection I can narrow the SUT to the initialization
// method. We still have to do 24 cases for testCalculateIsLooking...
when(controller.calculateIsLookingLikeABitch(brett, jules))
.thenReturn(Boolean.FALSE);
controller.initialize();
assertFalse(controller.doesLookLikeABitch());
}
}

30. public class GruePresenter {
public GruePresenter(Context context){
Crashlytics.start(context);
Log.d("GruePresenter", "Crashlytics Initialized");
// Even if you injected this. It would still be wrong
mixpanelAPI = MixpanelAPI.getInstance(context, MIXPANEL_TOKEN);
new YourFavoriteAsyncTask().execute(new DoSomethingNetworky());
throws new FacepalmException("You got eaten by a Grue!");
}
}
public class GruePresenterTest {
@Test(expects = FacepalmException.class)
public void testInitialization() throws Exception {
GruePresenter presenter = new GruePresenter(Robolectric.application);
// Your code is baaaaaaad and you should feel baaaaaaaad
}
}

31. public class GruePresenter {
// Remember, AsyncTask.execute is final!
public void doSomethingAsyncish(){
new YourFavoriteAsyncTask()
.execute(new
DoSomethingNetworky());
}
}
public class CrashlyticsAdapter {
public void start(Context context) {
Crashlytics.start(context);
}
}
public class Logger {
public void debug(String tag, String msg){
Log.d(tag, msg);
}
}
public class MixpanelAdapter {
// You can inject an instance of Mixpanel
public MixpanelWrapper(MixpanelAPI api) {
this.api = api;
}
}

32. public class GruePresenter {
public GruePresenter(CraslyticsWrapper crashlytics, Logger logger,
MixpanelWrapper mixpanelWapper){
crashlytics.start(context);
logger.debug("GruePresenter", "Crashlytics Initialized");
this.mixpanelWrapper = mixpanelWrapper;
// We had to move the doSomethingAsyncish out of here
}
}
public class GruePresenterTest {
@Test
public void testInitialization() throws Exception {
GruePresenter presenter = new GruePresenter(mockCrash, mockLogger,
mockMixpanel);
doNothing().when(presenter).doSomethingAsyncIsh()
// Alright, let’s dance!
}
}

33. “Aperture Science: We do what we must, because we can.”
Rolling

34. 2.397 Tests
● 2.364 units
● 33 integration
● 1.942 Android - coupled
~2:30m full test suite
~70% Coverage
Maven 3.2.3
● JUnit
● Mockito
● Robolectric
59 users, 7 crashes
~35K lines of code

35. 1. We are paid to solve problems. Be efficient.
1. Tests test what your code does, not what it should do.
1. If it is not your code, there is no need to test it.

37. Questions?
“Let me answer that question with a question: Who wants to make 60$?”

38. Bibliography
● xUnit Test Patterns: Refactoring Test Code, Gerard Meszaros
o http://xunitpatterns.com/
● 467 tests, 0 failures, 0 confidence, Katrina Owen
● Mocks aren’t stubs, Martin Fowler
● Eveyrthing you wanted to know about testing, but were afraid to ask, Jorge
Barroso
● Exploding Software-Engineering Myths, Janie Chang

39. “So you know what? You win. Just go.”
Thanks!