Elegant?? Unit Testing (Mobilization 2016)

In this session we will learn the basics of Unit Testing and its importance. We will define what a Unit Test is, what type of Unit Tests there are and then talk about Test Doubles. Finally, we will focus on how to write new tests and improve existing ones by reviewing some Android Github projects.

Can you sleep soundly without writing tests? Really???

Transcript

1. ELEGANT??
   UNIT TESTING
   by Pablo Guardiola
   @Guardiola31337
   

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2. TWITTER
   @Guardiola31337
   BLOG
   pguardiola.com/blog
   

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3. 4 rules of simple
   design
   1. Runs all the Tests
   

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4. 4 rules of simple
   design
   1. Runs all the Tests
   2. Reveals all the intention
   

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5. 4 rules of simple
   design
   1. Runs all the Tests
   2. Reveals all the intention
   3. No duplication
   

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6. 4 rules of simple
   design
   1. Runs all the Tests
   2. Reveals all the intention
   3. No duplication
   4. Fewest classes or methods
   

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7. What do they all
   AGREE on?
   

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8. PASSES its tests!
   

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9. Have you ever asked
   yourself, WHY?
   What MOTIVATES
   you to write tests?
   

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10. Testing motivators
    Validate the System
    

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11. Testing motivators
    Validate the System
    Code Coverage
    

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12. Testing motivators
    Validate the System
    Code Coverage
    Enable Refactoring
    

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13. Testing motivators
    Validate the System
    Code Coverage
    Enable Refactoring
    Document the Behaviour of the System
    

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14. Testing motivators
    Validate the System
    Code Coverage
    Enable Refactoring
    Document the Behaviour of the System
    Test Driven Development
    

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15. Testing motivators
    Validate the System
    Code Coverage
    Enable Refactoring
    Document the Behaviour of the System
    Test Driven Development
    Customer Acceptance
    

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16. Testing motivators
    Validate the System
    Code Coverage
    Enable Refactoring
    Document the Behaviour of the System
    Test Driven Development
    Customer Acceptance
    …
    

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17. Styles of Testing
    STATE
    VERIFICATION
    

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18. Styles of Testing
    STATE
    VERIFICATION
    BEHAVIOR
    VERIFICATION
    

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19. HYBRID
    

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20. Unit Test
    SOLITARY
    1. Never crosses boundaries
    

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21. Unit Test
    SOLITARY
    1. Never crosses boundaries
    2.The Class Under Test should be the only concrete
    class found in a test
    

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22. Unit Test
    SOLITARY
    SOCIABLE
    1. Never crosses boundaries
    2.The Class Under Test should be the only concrete
    class found in a test
    

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23. FIRST
    FAST
    

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24. FIRST
    FAST
    INDEPENDENT
    

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25. FIRST
    FAST
    INDEPENDENT
    REPEATABLE
    

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26. FIRST
    FAST
    INDEPENDENT
    REPEATABLE
    SELF-VALIDATING
    

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27. FIRST
    FAST
    INDEPENDENT
    REPEATABLE
    SELF-VALIDATING
    TIMELY
    

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28. Test Doubles
    DUMMY
    

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29. Dummy
    public class DummyAuthorizer implements Authorizer {

    @Override

    public Boolean authorize(String username, String password) {

    return null;

    }

    }
    

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30. Test Doubles
    DUMMY
    STUB
    

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31. Stub
    public class AcceptingAuthorizerStub implements Authorizer {

    @Override

    public Boolean authorize(String username, String password) {

    return true;

    }

    }
    

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32. Test Doubles
    DUMMY
    STUB
    SPY
    

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33. Spy
    public class AcceptingAuthorizerSpy implements Authorizer {

    public boolean authorizeWasCalled = false;

    

    public Boolean authorize(String username, String password) {

    authorizeWasCalled = true;

    return true;

    }

    }
    

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34. Test Doubles
    DUMMY
    STUB
    SPY
    MOCK
    

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35. Mock
    public class AcceptingAuthorizerVerificationMock implements Authorizer {

    public boolean authorizeWasCalled = false;

    

    public Boolean authorize(String username, String password) {

    authorizeWasCalled = true;

    return true;

    }

    

    public boolean verify() {

    return authorizeWasCalled;

    }

    }
    

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36. Test Doubles
    DUMMY
    STUB
    SPY
    MOCK
    FAKE
    

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37. Fake
    public class AcceptingAuthorizerFake implements Authorizer {

    public Boolean authorize(String username, String password) {

    return username.equals("Bob");

    }

    }
    

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38. AAA
    ARRANGE
    

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39. AAA
    ARRANGE
    ACT
    

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40. AAA
    ARRANGE
    ACT
    ASSERT
    

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41. What about
    ANDROID?
    

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42. ANDROID Unit Testing
    Java Module
    

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43. ANDROID Unit Testing
    Java Module
    AS 1.1 + Android Gradle Plugin
    

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44. ANDROID Unit Testing
    Java Module
    MVP
    AS 1.1 + Android Gradle Plugin
    

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45. ANDROID Unit Testing
    Java Module
    MVP
    AS 1.1 + Android Gradle Plugin
    MVVM
    

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46. ANDROID Unit Testing
    Java Module
    MVP
    CLEAN Architecture
    AS 1.1 + Android Gradle Plugin
    MVVM
    

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47. ANDROID Unit Testing
    Java Module
    MVP
    CLEAN Architecture
    AS 1.1 + Android Gradle Plugin
    MVVM
    Catan Architecture
    

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48. ANDROID Unit Testing
    Java Module
    Mosby
    MVP
    CLEAN Architecture
    AS 1.1 + Android Gradle Plugin
    MVVM
    Catan Architecture
    

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49. ANDROID Unit Testing
    Java Module
    Rosie
    Mosby
    MVP
    CLEAN Architecture
    AS 1.1 + Android Gradle Plugin
    MVVM
    Catan Architecture
    

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50. ANDROID Unit Testing
    …
    Java Module
    Rosie
    Mosby
    MVP
    CLEAN Architecture
    AS 1.1 + Android Gradle Plugin
    MVVM
    Catan Architecture
    

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51. DECOUPLED
    Architecture
    

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52. Where do I
    START?
    

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53. public class FooTest {

    

    @Test

    public void sampleTest() throws Exception {

    assertEquals(expected, actual);

    }

    }
    JUnit
    

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54. Clean Contacts
    @Test public void obtainContactFirstNameFromRepo() throws Exception {

    ContactsBddDataSource mockContactsBddDataSource =
    mock(ContactsBddDataSource.class);

    ContactsNetworkDataSource mockContactsNetworkDataSource =
    mock(ContactsNetworkDataSource.class);

    ContactsRepositoryImp contactsRepository =

    new ContactsRepositoryImp(mockContactsNetworkDataSource,
    mockContactsBddDataSource);

    Contact mobilization = new Contact();

    Name name = new Name();

    name.setFirst(“Mobilization 2016");

    mobilization.setName(name);

    when(mockContactsBddDataSource.obtain(“MobilizationMD5")).thenReturn(droidCon);

    

    Contact contact = contactsRepository.obtain("MobilizationMD5");

    

    assertEquals("Mobilization 2016", contact.getName().getFirst());

    }
    

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55. Clean Contacts
    @Test public void contactsInteractorExecutedWhenResumed() throws Exception {

    InteractorInvoker interactorInvoker = mock(InteractorInvoker.class);

    GetContactsInteractor getContactsInteractor = mock(GetContactsInteractor.class);

    final ListMapper listMapper = mock(ListMapper.class);

    ThreadSpec mainThreadSpec = mock(ThreadSpec.class);

    MainPresenter mainPresenter =

    new MainPresenter(interactorInvoker, getContactsInteractor, listMapper,
    mainThreadSpec);

    

    mainPresenter.onResume();

    

    verify(interactorInvoker).execute(Mockito.eq(getContactsInteractor),
    Mockito.any(InteractorOutputImp.class));

    }
    

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56. How do I IMPROVE
    my tests?
    DAMP
    

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57. One Assertion Per Test
    (State Verification)
    @Test public void shouldCreateVerboseTraceFromStringTrace() throws Exception {

    Trace trace = Trace.fromString(VERBOSE_TRACE);

    

    assertEquals(TraceLevel.VERBOSE, trace.getLevel());

    assertEquals(ANY_TRACE_DATE + " " + VERBOSE_TRACE_MESSAGE, trace.getMessage());

    }
    

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58. It’s ANNOYING to have to look
    at the STACKTRACE to know
    what’s FAILING
    

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59. It’s ANNOYING to have to look
    at the STACKTRACE to know
    what’s FAILING
    Have NO INFORMATION
    about REMAINING TESTS
    

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60. One Assertion Per Test
    (Behavior Verification)
    @Test public void shouldNotUpdateFilterIfPresenterIsNotInitialized() {

    presenter.updateFilter(ANY_FILTER);

    

    verify(lynx, never()).setConfig(any(LynxConfig.class));

    verify(lynx, never()).restart();

    }
    

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61. Expect Literals
    @Test

    public void testSaveAllNextLevel() throws Exception {

    doReturn(Boolean.TRUE).when(repository).hasNextLevel();

    

    assertEquals(elements.size(), repository.saveAll(elements).size());

    verify(nextLevel, times(1)).saveAll(anyCollection());

    }
    

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62. Expect Literals
    @Test

    public void testSaveAllNextLevel() throws Exception {

    doReturn(Boolean.TRUE).when(repository).hasNextLevel();

    

    assertEquals(3, repository.saveAll(elements).size());

    verify(nextLevel, times(1)).saveAll(anyCollection());

    }
    

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63. READABILITY
    LITERALS will
    REFLECT the examples
    from the BUSINESS
    

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64. Value Objects vs Expect Literals
    CONVERT
    VALUE OBJECT into
    a LITERAL
    

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65. Avoid Inline Setup
    @Before

    public void setUp() throws Exception {

    initMocks(this);

    

    elements.add(mockedElement1);

    elements.add(mockedElement2);

    elements.add(mockedElement3);

    

    ids.add(EXPECTED_FIRST_ID);

    ids.add(EXPECTED_SECOND_ID);

    ids.add(EXPECTED_THIRD_ID);

    

    repository = new BaseFastRepositoryImpl(currentLevel, null);

    }
    

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66. READABILITY
    Avoid CODE DUPLICATION?
    BUILDERS
    

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67. Questionable Tests
    Testing Language Features or
    Standard Library Classes
    

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68. Questionable Tests
    Testing Language Features or
    Standard Library Classes
    Testing Framework Features
    or Classes
    

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69. Don’t test your stubs
    @Test

    public void doNotTestYourStubs() throws Exception {

    Name name = mock(Name.class);

    // blah blah blah...

    when(name.getFullName()).thenReturn("Don't test your stubs, please!");

    // 27 lines of stuff...

    assertEquals("Don't test your stubs, please!", name.getFullName());

    }
    

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70. Should we even bother
    writing Unit Tests?
    “The key is to test the areas that you are most
    worried about going wrong. That way you get
    the most benefit for your testing effort.”
    Martin Fowler, Refactoring
    

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71. “Practise makes perfect.”
    

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72. ELEGANT??
    UNIT TESTING
    @Deprecated
    

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73. Thank you!
    @Guardiola31337
    pguardiola.com
    guardiola31337@gmail.com
    

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74. Extreme Programming Explained: Embrace Change, Kent Beck, AddisonWesley.
    Working Effectively with Unit Tests by Jay Fields
    Bibliography
    Mocks Aren’t Stubs (www.martinfowler.com/articles/mocksArentStubs.html)
    The Little Mocker (blog.8thlight.com/uncle-bob/2014/05/14/TheLittleMocker.html)
    https://github.com/PaNaVTEC/Clean-Contacts
    https://github.com/pedrovgs/Lynx
    https://github.com/Guardiola31337/CatanArchitecture
    Ted Mosby - Software Architect (http://hannesdorfmann.com/android/mosby)
    Responsible Design for Android by J. B. Rainsberger
    Clean Code: A handbook of Agile Software Craftsmanship, Robert C. Martin
    Software Craftsmanship by Sandro Mancuso
    

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