The document discusses Test-Driven Development (TDD) practices for Android, detailing the process for implementing functionality through automated tests, including examples of passing and failing tests. It highlights the architecture of Android testing frameworks such as ActivityInstrumentationTestCase2, and features code snippets for testing features like timeline display. Additionally, it covers optimizations for async loading and provides examples of integration and unit tests, concluding with references and resources for further exploration.

1. Android
TDD &
Marcin Gryszko
@mgryszko

2. New
gig

3. User stories
written

4. Kickoff?

5. walking
skeleton
“Implementation of the
thinnest possible slice of
real functionality that we
can automatically build,
deploy, and test end-to-
end”
original idea by Alistair Cockburn

6. Iteration “zero”
TDD cycle

7. 0
1. Understand the problem
2. Think about architecture
3. Automate

8. Android testing framework

9. Architecture

10. Automate

11. + Android
plugin

13. Failing acceptance test
public class TimelineTest extends ActivityInstrumentationTestCase2<TimelineActivity> {
public void test_chirps_are_displayed_timely_ordered() throws Exception {
timelineDriver.waitUntilTimelineLoaded(mgryszkosChirps().size());
assertTimelineEqualTo(timelineDriver.getDisplayedTimeline(), mgryszkosChirps());
}
}

14. Failing acceptance test
public class TimelineTest extends ActivityInstrumentationTestCase2<TimelineActivity> {
public void test_chirps_are_displayed_timely_ordered() throws Exception {
timelineDriver.waitUntilTimelineLoaded(mgryszkosChirps().size());
assertTimelineEqualTo(timelineDriver.getDisplayedTimeline(), mgryszkosChirps());
}
}

15. Page object
public class TimelineDriver {
private Solo solo;
public TimelineDriver(Solo solo) { this.solo = solo; }
public void waitUntilTimelineLoaded(int timelineSize) {
solo.waitForView(TableRow.class, timelineSize, 5000);
}
public List<Chirp> getDisplayedTimeline() {
ListView timelineView = (ListView) solo.getView(R.id.timelineView);
List<Chirp> chirps = new ArrayList<Chirp>();
for (int i = 0; i < timelineView.getCount(); i++) {
chirps.add((Chirp) timelineView.getItemAtPosition(i));
}
return chirps;
}
}

16. Failing acceptance test
public class TimelineTest extends ActivityInstrumentationTestCase2<TimelineActivity> {
private Solo solo;
private TimelineDriver timelineDriver;
protected void setUp() throws Exception {
super.setUp();
solo = new Solo(getInstrumentation(), getActivity());
timelineDriver = new TimelineDriver(solo);
}
public void test_chirps_are_displayed_timely_ordered() throws Exception {
timelineDriver.waitUntilTimelineLoaded(mgryszkosChirps().size());
assertTimelineEqualTo(timelineDriver.getDisplayedTimeline(), mgryszkosChirps());
}
private void assertTimelineEqualTo(List<Chirp> actual, List<Chirp> expected) {
assertEquals(expected, actual);
}
}

17. Passing acceptance test
public class TimelineActivity extends Activity {
public void onCreate(Bundle savedInstanceState) { // super.onCreate & setContentView omitted
List<Chirp> chirps = loadTimeline();
displayTimeline(chirps);
}
private List<Chirp> loadTimeline() {
return executeJsonRequest("http://...", "mgryszko");
}
private List<Chirp> executeJsonRequest(String uri, Object... requestParams) {
RestTemplate restTemplate = new RestTemplate();
return asList(restTemplate.getForObject(uri, Chirp[].class, requestParams));
}
private void displayTimeline(List<Chirp> chirps) {
TimelineAdapter adapter = new TimelineAdapter();
adapter.setActivity(this);
adapter.setChirps(chirps);
ListView timelineView = (ListView) findViewById(R.id.timelineView);
timelineView.setAdapter(adapter);
}
}

18. Tracer bullet
hit

19. Let’s
ref
ac
tor

20. Hamcrest
public class TimelineTest extends ActivityInstrumentationTestCase2<TimelineActivity> {
private void assertTimelineEqualTo(List<Chirp> actual, List<Chirp> expected) {
assertEquals(expected, actual);
}
}

21. Hamcrest
public class TimelineTest extends ActivityInstrumentationTestCase2<TimelineActivity> {
private void assertTimelineEqualTo(List<Chirp> actual, List<Chirp> expected) {
assertThat(actual.size(), equalTo(expected.size()));
for (Chirp chirp : expected) {
assertThat(format("Chirp %s not in the timeline", chirp), actual, hasItem(chirp));
}
}
}

22. Roboguice
public class TimelineActivity extends Activity {
private void displayTimeline(List<Chirp> chirps) {
TimelineAdapter adapter = new TimelineAdapter();
adapter.setActivity(this);
adapter.setChirps(chirps);
ListView timelineView = (ListView) findViewById(R.id.timelineView);
timelineView.setAdapter(adapter);
}
}

23. Roboguice
public class TimelineActivity extends RoboActivity {
@InjectView(R.id.timelineView)
private ListView timelineView;
private void displayTimeline(List<Chirp> chirps) {
TimelineAdapter adapter = getInjector()
.getInstance(TimelineAdapter.class)
.withChirps(chirps));
timelineView.setAdapter(adapter);
}
}

24. Falling integration test
public class ChirpJsonRepositoryTest extends TestCase {
private ChirpRepository repository = new ChirpJsonRepository();
public void test_returns_the_timeline_of_a_chirper() {
assertTimelineEqualTo(repository.findTimelineOf("mgryszko"), mgryszkosChirps());
}
}

25. Passing integration test
public class ChirpJsonRepository implements ChirpRepository {
public List<Chirp> findTimelineOf(String chirper) {
return executeJsonRequest("http://...", chirper);
}
private List<Chirp> executeJsonRequest(String uri, Object... requestParams) {
RestTemplate restTemplate = new RestTemplate();
return asList(restTemplate.getForObject(uri, Chirp[].class, requestParams));
}
}

26. Passing integration test
public class TimelineActivity extends Activity {
private List<Chirp> loadTimeline() {
return executeJsonRequest("http://...", "mgryszko");
}
private List<Chirp> executeJsonRequest(String uri, Object... requestParams) {
RestTemplate restTemplate = new RestTemplate();
return asList(restTemplate.getForObject(uri, Chirp[].class, requestParams));
}
}

27. Passing integration test
public class TimelineActivity extends RoboActivity {
@Inject
private ChirpRepository chirpRepository;
private List<Chirp> loadTimeline() {
return chirpRepository.findTimelineOf("mgryszko");
}
}

28. Optimization

29. Async loading
public class TimelineActivity extends RoboActivity
implements TimelineLoadListener {
@Inject
private AsyncTimelineLoader timelineLoader;
private void loadTimeline() {
timelineLoader.loadChirperTimeline("mgryszko", this);
}
public void timelineLoaded(List<Chirp> timeline) {
displayTimeline(timeline);
}
}
public interface TimelineLoadListener {
void timelineLoading();
void timelineLoaded(List<Chirp> timeline);
}

30. Async loading
public class TimelineLoadTask extends RoboAsyncTask<List<Chirp>>
implements AsyncTimelineLoader {
public void loadChirperTimeline(String chirper, TimelineLoadListener loadListener) {
this.execute();
}
@Override
protected void onPreExecute() throws Exception {
loadListener.timelineLoading();
}
public List<Chirp> call() throws Exception {
return repository.findTimelineOf(chirper);
}
@Override
protected void onSuccess(List<Chirp> chirps) throws Exception {
loadListener.timelineLoaded(chirps);
}
}

31. First unit test
public class TimelineLoadTaskTest extends RoboUnitTestCase<Application> {
private Mockery context = new Mockery();
private ChirpRepository repository = context.mock(ChirpRepository.class);
private TimelineLoadListener loadListener = context.mock(TimelineLoadListener.class);
public void test_loads_timeline_successfully_and_notifies_the_listener() {
TimelineLoadTask task = createTimelineLoadTask();
context.checking(new Expectations() {{
List<Chirp> timeline = asList(A_CHIRP);
oneOf(loadListener).timelineLoading();
oneOf(repository).findTimelineOf(CHIRPER); will(returnValue(timeline));
oneOf(loadListener).timelineLoaded(with(timeline));
}});
executeInFakeUIThread(task);
}
}

32. First unit test
private CountDownLatch taskDone = new CountDownLatch(1);
private TimelineLoadTask createTimelineLoadTask() {
return new TimelineLoadTask(repository) {
@Override
protected void onFinally() {
taskDone.countDown();
}
};
}
private void executeInFakeUIThread(final TimelineLoadTask task) {
new RoboLooperThread() {
public void run() {
task.loadChirperTimeline(CHIRPER, loadListener);
}
}.start();
taskDone.await();
}
}

33. Really unit?

34. straight JUnit
IntelliJ
java.lang.RuntimeException: Stub!
at junit.runner.BaseTestRunner.(BaseTestRunner.java:5)
Maven
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.024
sec

35. TestNG
IntelliJ
===============================================
Custom suite
Total tests run: 1, Failures: 0, Skips: 0
===============================================
Maven
Running TestSuite
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.298
sec

36. Robolectric
@RunWith(InjectingTestRunner.class)
public class TimelineUnitTest {
@Inject
private TimelineActivity activity;
@Inject
private AsyncTimelineLoaderStub timelineLoader;
@Test
public void triggers_timeline_loading() {
activity.onCreate(NO_SAVED_INSTANCE_STATE);
assertThat(timelineLoader.isTimelineLoaded(), is(true));
}
@Test
public void progress_dialog_is_displayed_when_timeline_is_loaded() {
activity.timelineLoading();
assertThat(Robolectric.shadowOf(activity).getLastShownDialogId(),
is(TimelineActivity.PROGRESS_DIALOG_ID));
}
}

37. Wrap-up

38. Thanks!

39. https://github.com/mgryszko/android-
tdd-ci

40. you
?
jobs Marcin
@
osoco.es

41. Image sources:
http://www.flickr.com/photos/sarah_mccans/219287847/
http://www.flickr.com/photos/f-oxymoron/5005146417/
http://www.bluebison.net/content/2007/a-skeleton-walking-his-pets/
http://www.flickr.com/photos/familymwr/5009855774/
http://www.flickr.com/photos/zbraineater/2213219097/
http://www.flickr.com/photos/stusev/3296738594/
http://www.flickr.com/photos/hadamsky/293310259/
http://www.flickr.com/photos/qthomasbower/3392847831/
http://www.flickr.com/photos/mikecogh/5113779851/