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Unit testing on Android (Droidcon Dubai 2015)
The document discusses unit testing in Android development, highlighting the importance of testing code to ensure functionality and maintainability. It outlines methods for writing tests, tools like Robolectric, and best practices for structuring tests effectively. Additionally, it emphasizes the necessity for clean code and dependency injection to facilitate testing.
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Similar to Unit testing on Android (Droidcon Dubai 2015)
Unit testing on Android (Droidcon Dubai 2015)
- 1. Unit Tes)ng on Android Danny Preussler GROUPON DroidCon Dubai test (c) DaveBleasdale, CC by 2.0, www.flickr.com/photos/sidelong/246816211
- 2. Groupon is the global leader in local commerce, making it easy for people around the world to search ! and discover great businesses at unbeatable prices. Source: Internal data,, March 2014 WORLDWIDE! 260M+ subscribers 53.9M active customers 500+ markets 900M+ deals sold 2 $5B+ in annual billings 12,000+ global employees
- 3. Leading the way in mobile commerce Our mobile app is available in 43 countries. Groupon’s vibrant mobile marketplace connects! consumers with their local economy 3 Sources: Internal Data; iTunes ranking for US stores available here - https://itunes.apple.com/WebObjects/ MZStore.woa/wa/viewFeature?id=500873243&mt=8&v0=www-itunes25Bcountdown-appstore Nearly 110 million people worldwide have downloaded our mobile app at the end of Q4 2014. One of the 25 most downloaded free apps of all time More than 50% of our Global transactions were completed on a mobile device by the end of Q4 2014
- 4. About Me? • GrouponBerlin • Groupon Merchant App • Unit Test enthusiast
- 5. What people say about unit tes0ng • Slows you down • I know my code is working! • Only have UI Code Day 27/365 -‐ Imagina)on.. by Caden Crawford, CC by 2.0, flickr.com/ photos/cadencrawford/8422302030
- 6. What is aUnit Test? • Small Opposite of an end-‐to-‐end-‐test test the smallest unit possible • You should have LOTS of them • Fast!!!! er by www.GlynLowe.com, CC by 2.0, flickr.com/photos/glynlowe/10921728045
- 7. Why Unit test? • Documents behaviour • Refactoring not possible without! • Gives trust • Only slows down if you don‘t have )me for quality code and tes)ng anyway Day 27/365 -‐ Imagina)on.. by Caden Crawford, CC by 2.0, flickr.com/photos/cadencrawford/8422302030
- 8. Why Unit test? Code without Test = Legacy code Only Bad Code is untestable! Day 27/365 -‐ Imagina)on.. by Caden Crawford, CC by 2.0, flickr.com/photos/cadencrawford/8422302030
- 9. SOLID FOUNDATIONFlughafen Berlin-Brandenburg, Blickin die Abflughalle by Muns CC BY 3.0 http://commons.wikimedia.org/wiki/File:120513-BER-innen.JPG
- 10. App development reality Tidygarage by Bryn Pinzgauer CC 2.0 http://www.flickr.com/photos/12394349@N06/4492572621/in/photostream/
- 11. Pure JUnit? java.lang.RuntimeException: Stub! AndroidFirewall by Uncalno, CC BY 2.0 flickr.com/photos/uncalno/8538679708
- 12. Robolectric New Android UnitTesting Lost Horizons -‐ Light by Simon & His Camera, CC by 2.0 flickr.com/ph
- 13. New Android UnitTesting • still experimental • hdp://tools.android.com/tech-‐docs/unit-‐tes)ng-‐support • Project structure: src/main/java/Foo.java src/test/java/FooTest.java • gradle: android { testOptions { unitTests.returnDefaultValues = true } Lost Horizons -‐ Light by Simon & His Camera, CC by 2.0 flickr.com/photos/simon__syon/14842606832
- 14. What to test? Start your engine by Norlando Pobre, CC by 2.0, flickr.com/photos/npobre/2601582256
- 15. Great Wall ofChina (IV) by isawnyu. CC 2.0 http:// www.flickr.com/photos/isawnyu/7183821643/in/photostream/ Separate Java and Android Code?
- 16. Great Wall ofChina (IV) by isawnyu. CC 2.0 http:// www.flickr.com/photos/isawnyu/7183821643/in/photostream/ Separate Java and Android Code? Android is not Java+UI Intent, Bundle, SparseArray, Uri.. not fancy device classes! You will never reuse this on another Java platform, stop pretending! Context everywhere Recreate the System? (interface UI {...} ?)
- 17. You can test everything! Typing the universe by Feliciano Guimarães, CC by 2.0, flickr.com/photos/jsome1/6097841770
- 18. „Mock“??? Martin Fowler: „test-doubles... pre-programmed with expectations “ Typing the universe by Feliciano Guimarães, CC by 2.0, flickr.com/photos/jsome1/6097841770
- 19. Typing the universe by Feliciano Guimarães, CC by 2.0, flickr.com/photos/jsome1/6097841770 Mock TelephonyManager mgr = mock(TelephonyManager.class); when(mgr.getDeviceId()) .thenReturn("123456"); ...
- 20. Spy MyPreferences pref= spy(new MyPreferences(context)); … verify(pref).saveTitle(same(title)); verify(pref).savePersonalData(anyString()); She spy by Kangrex, CC by 2.0; flickr.com/photos/kangrex/3012574701
- 21. Building blocks ofa Test public class AndroidAccountsTest { AccountManager manager; AndroidAccounts tested; @Before public void setup() {...} @Test public void should_get_token() { when(manager.peekAuthToken(....)).thenReturn("token"); String token = tested.getCurrentToken(...) assertEquals("token", token); } } swivel-‐snot by Linus Bohman, CC 2.0, flickr.com/photos/bohman/16062901379
- 22. Easy... • Test u)lity classes • Test JSON parsing • Test API layer Duplo Pac-‐Man by Dan Diemer, CC by 2.0, flickr.com/photos/diemer/192740446
- 23. Gson gson =GsonFactory.getGson(); @Test public void should_parse_json_data() { String values = inputStreamToString(„auth.json")); AuthRslt rslt = gson.fromJson(values, AuthRslt.class); assertEquals("AQAAAABwgQ2vVzk-KjiEA3“, result.getAccessToken()); } Easy... Duplo Pac-‐Man by Dan Diemer, CC by 2.0, flickr.com/photos/diemer/192740446
- 24. Easy when you do it right • Test user interac)on (click etc) • Test Fragments and Ac)vi)es Lego small car. by Do-‐Hyun Kim, CC by 2.0, flickr.com/photos/s)ckkim/6805370739
- 25. class NavFragment extendsInjectedFragment { Interactor interactor; @OnClick(R.id.nav_button_checkout) public void onClickCheckout() { interactor.moveToCheckout( getActivity()); } } User interac)on Lego small car. by Do-‐Hyun Kim, CC by 2.0, flickr.com/photos/s)ckkim/6805370739 Test for this is trivial!
- 26. Screen changes @Test publicvoid should_do_transaction() { TransactionUtil transactionsUtil = mock(TransactionUtil.class), tested.showPaymentMethods( transactionsUtil, mock(Purchase.class)); verify(transactionsUtil) .addAllowingStateLoss( any(FragmentManager.class), eq(android.R.id.content), isA(PaymentFragment.class)); } Lego small car. by Do-‐Hyun Kim, CC by 2.0, flickr.com/photos/s)ckkim/6805370739
- 27. Screen changes Lego small car. by Do-‐Hyun Kim, CC by 2.0, flickr.com/photos/s)ckkim/6805370739 • Robolectric offers FragmentTranscta)ons and life cycle method: • Robolectric .buildActivity( Activity.class) .attach() .create()..... • Careful, feature flaky
- 28. Screen changes Lego small car. by Do-‐Hyun Kim, CC by 2.0, flickr.com/photos/s)ckkim/6805370739 • Easier: Field field = Fragment.class.getDeclaredField("mActivity"); field.setAccessible(true); field.set(fragmentInstance, mock(Activity.class); • You might need also to mock getResources()
- 29. Harder but possible • Test UI code LEGO 10179 Ul)mate Collector's Millenium Falcon™ by Do-‐Hyun Kim, CC by 2.0, flickr.com/photos/s)ckkim/6966161598
- 30. Test UI code public class BorderPainterTest { Canvas canvas = mock(Canvas.class); Circle circle = mock(Circle.class); BorderPainter tested = new BorderPainter(); @Test public void should_draw_two_circles() { ... tested.drawBorder(new RectF(), canvas, circle); InOrder inOrder = inOrder(canvas); inOrder.verify(canvas).drawCircle( anyFloat(), anyFloat(), eq(10f), any(Paint.class)); inOrder.verify(canvas).drawCircle( anyFloat(), anyFloat(), eq(20f), any(Paint.class)); } } LEGO 10179 Ul)mate Collector's Millenium Falcon™ by Do-‐Hyun Kim, CC by 2.0, flickr.com/photos/s)ckkim/6966161598
- 31. Wri)ng testable code... • Clean Code • Separa)on of Concerns Manual Inside by Masked Builder, CC by 2.0, flickr.com/photos/masked-‐builder/8517238602
- 32. Dependency Injec)on helps • Don‘t create dependencies yourself • Invert Control! • Inject them! construct by Len Madhews, CC by 2.0; flickr.com/photos/mythoto/16412713709 Syringe with Green Liquid by Andres Rueda, CC by 2.0; lickr.com/photos/andresrueda/16558374828
- 33. If it‘s hard to test... • Class is too large • Class is doing too many things • Class knows too many things Modified condi)on/decision coverage for cri)cal souware tes)ng by Nguyen Hung Vu, CC by 2.0, www.flickr.com/photos/vuhung/14621502361
- 34. Make it fail! Apple Mini DisplayPort adapter FAIL by David Joyce, CC by 2.0, flickr.com/photos/deapeajay/2969264395
- 35. 1 method = 1 test? • Test all cases, else you might miss sth • one method should have mul)ple test (although coverage already reached with first) • Don‘t be super strict on units, some)mes end to end might make sense i.e. json parsing into models with full Json
- 36. Coverage? • You should Measure • Mo)vates! • Don‘t trust too much into it
- 37. When to use Robolectric • Parcel Tests • Arguments/Bundle Tests • Resource loading Tests
- 38. Parcel Tests with Robolectric @RunWith(RobolectricTestRunner.class) public class UserTest { Parcel parcel = Parcel.obtain(); User tested = new User("123", "456"); @Test public void check_parcel_implementa)on() { tested.writeToParcel(parcel, 0); parcel.setDataPosi)on(0); User out = User.CREATOR.createFromParcel(parcel); assertEquals("123", out.getUser()); assertEquals("456", out.getPassword()); }
- 39. Resource Tests with Robolectric @Test @Config(qualifiers = "en") public void getTotalAuerTaxLong() { assertEquals( "$10.00 Due“, tested.getTotalAuerTaxLong(1000)); }
- 40. Layout tests with Robolectric @Test public void checkPhoneNumberIsHidden() { MyActivity activity = new MyActivity(); activity.onCreate(); TextView tv = (TextView) activity.findViewById(R.id.callText); assertEquals(View.GONE, tv.getVisibility()); }
- 41. Dead End -‐ mid by bennylin0724, CC BY 2.0 flickr.com/photos/benny_lin/191393604
- 42. Test all the Things! Start your engine by Norlando Pobre, CC by 2.0, flickr.com/photos/npobre/2601582256
- 43. THANK YOU Danny Preussler GROUPON Berlin dpreussler@groupon.com
- 44. github.com/groupon engineering.groupon.com Michael Burton, Roboguice Carlos Sessa, 50 Android hacks David van der Bokke, RoboRemote David Willson, Odo …. Stephane Nicolas, RoboSpice Par)al Supermen, juliegomoll, CC by 2.0, flickr.com/photos/juliegomoll/1352843346