Clean Architecture & TDD

Clean Architecture & TDD @Android Test Night #1
https://testnight.connpass.com/event/63753/

Transcript

1. Clean Architecture &
   TDD
   @fushiroyama
   

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2. About Me
   • Fumihiko Shiroyama
   • Android App Developer
   • Unit Test Enthusiast
   • https://github.com/srym
   

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3. Clean Architecture
   • Presentation
   • Domain
   • Infrastructure
   

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4. TDD
   • Test Driven Development
   • Test First
   • Minimum Implementation
   • Refactoring
   

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5. TDD is great! because...
   • Focus on I/O
   • Less reworking
   • Force Unit Testing
   

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6. Example
   • Infrastructure
   • Remote Data Source
   • GitHub Information
   • Local Unit Test
   

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7. Interface
   public interface RemoteGitHubDataSource {
   Single> listRepos(@NonNull String user);
   }
   

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8. Blank Implementation
   public class RestGitHubDataSource
   implements RemoteGitHubDataSource {
   @Override
   public Single> listRepos(@NonNull String user) {
   return Single.error(new RuntimeException());
   }
   }
   

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9. Blank Implementation
   public class RestGitHubDataSource
   implements RemoteGitHubDataSource {
   @Override
   public Single> listRepos(@NonNull String user) {
   return Single.error(new RuntimeException());
   }
   }
   

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10. Create Test
    • Mouse over class
    • Alt + Enter
    • Create Test
    

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11. Create Test
    

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12. Create Test
    

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13. By the way...
    • Mouse over class
    • Shift + Command + T
    • Choose Test
    

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14. Test First
    public class RestGitHubDataSourceTest {
    private RestGitHubDataSource dataSource;
    @Before
    public void setUp() throws Exception {
    dataSource = new RestGitHubDataSource();
    }
    @Test
    public void listRepos() throws Exception {
    // implement here!
    }
    }
    

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15. Test First
    @Test
    public void listRepos() throws Exception {
    List repos = restGitHubDataSource.listRepos("srym")
    .test()
    .await()
    .assertNoErrors()
    .assertComplete()
    .values()
    .get(0);
    assertThat(repos).isNotNull();
    }
    

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16. Test First
    assertThat(repos).isNotNull().isNotEmpty();
    Repo repo = repos.get(0);
    assertThat(repo).isNotNull();
    assertThat(repo.getFullName()).isNotBlank();
    assertThat(repo.getId()).isGreaterThanOrEqualTo(0);
    assertThat(repo.getOwner()).isNotNull();
    

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17. Test First
    assertThat(repos).isNotNull().isNotEmpty();
    Repo repo = repos.get(0);
    assertThat(repo).isNotNull();
    assertThat(repo.getFullName()).isNotBlank();
    assertThat(repo.getId()).isGreaterThanOrEqualTo(0);
    assertThat(repo.getOwner()).isNotNull();
    You can confirm the specs
    BEFORE you implement
    

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18. Test Execution (failure)
    • This of course fails.
    

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19. Minimum Implementation
    public class RestGitHubDataSource implements RemoteGitHubDataSource {
    private final GitHubService gitHubService;
    @Inject
    public RestGitHubDataSource(GitHubService gitHubService) {
    this.gitHubService = gitHubService;
    }
    @Override
    public Single> listRepos(@NonNull String user) {
    return gitHubService.listRepos(user);
    }
    }
    

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20. Minimum Implementation
    public class RestGitHubDataSource implements RemoteGitHubDataSource {
    private final GitHubService gitHubService;
    @Inject
    public RestGitHubDataSource(GitHubService gitHubService) {
    this.gitHubService = gitHubService;
    }
    @Override
    public Single> listRepos(@NonNull String user) {
    return gitHubService.listRepos(user);
    }
    }
    

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21. Minimum Implementation
    public class RestGitHubDataSource implements RemoteGitHubDataSource {
    private final GitHubService gitHubService;
    @Inject
    public RestGitHubDataSource(GitHubService gitHubService) {
    this.gitHubService = gitHubService;
    }
    @Override
    public Single> listRepos(@NonNull String user) {
    return gitHubService.listRepos(user);
    }
    }
    

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22. But wait...
    • This is Local Unit Test
    • Mock data? Hmm.
    

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23. MockWebServer
    

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24. MockWebServer
    • Provided by OkHttp
    • Full HTTP Stack
    • Can test REAL response
    

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25. MockWebServer
    private final MockWebServer mockWebServer
    = new MockWebServer();
    

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26. MockWebServer
    Dispatcher dispatcher = new Dispatcher() {
    @Override
    public MockResponse dispatch(RecordedRequest request)
    throws InterruptedException {
    return new MockResponse().setResponseCode(404);
    }
    };
    mockWebServer.setDispatcher(dispatcher);
    mockWebServer.start();
    

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27. MockWebServer
    @Override
    public MockResponse dispatch(RecordedRequest request) throws
    InterruptedException {
    if (request == null || request.getPath() == null) {
    return new MockResponse().setResponseCode(400);
    }
    if (request.getPath().matches("/users/.+/repos")) {
    return new MockResponse()
    .setBody(readJsonFromResources("users_repos.json"))
    .setResponseCode(200);
    }
    return new MockResponse().setResponseCode(404);
    }
    

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28. MockWebServer
    @Override
    public MockResponse dispatch(RecordedRequest request) throws
    InterruptedException {
    if (request == null || request.getPath() == null) {
    return new MockResponse().setResponseCode(400);
    }
    if (request.getPath().matches("/users/.+/repos")) {
    return new MockResponse()
    .setBody(readJsonFromResources("users_repos.json"))
    .setResponseCode(200);
    }
    return new MockResponse().setResponseCode(404);
    }
    

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29. MockWebServer
    @Override
    public MockResponse dispatch(RecordedRequest request) throws
    InterruptedException {
    if (request == null || request.getPath() == null) {
    return new MockResponse().setResponseCode(400);
    }
    if (request.getPath().matches("/users/.+/repos")) {
    return new MockResponse()
    .setBody(readJsonFromResources("users_repos.json"))
    .setResponseCode(200);
    }
    return new MockResponse().setResponseCode(404);
    }
    

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30. MockWebServer
    @Override
    public MockResponse dispatch(RecordedRequest request) throws
    InterruptedException {
    if (request == null || request.getPath() == null) {
    return new MockResponse().setResponseCode(400);
    }
    if (request.getPath().matches("/users/.+/repos")) {
    return new MockResponse()
    .setBody(readJsonFromResources("users_repos.json"))
    .setResponseCode(200);
    }
    return new MockResponse().setResponseCode(404);
    }
    Talk about this later
    

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31. MockWebServer
    Retrofit retrofit = new Retrofit.Builder()
    .baseUrl(mockWebServer.url(""))
    .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
    .addConverterFactory(GsonConverterFactory.create())
    .build();
    GitHubService gitHubService = retrofit.create(GitHubService.class);
    

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32. MockWebServer
    Retrofit retrofit = new Retrofit.Builder()
    .baseUrl(mockWebServer.url(""))
    .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
    .addConverterFactory(GsonConverterFactory.create())
    .build();
    GitHubService gitHubService = retrofit.create(GitHubService.class);
    

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33. Prepare Data
    • Curl
    • Postman
    curl https://api.github.com/users/srym/repos >
    users_repos.json
    

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34. Prepare Data
    • Put it test/resources
    

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35. Read JSON from file
    private String readJsonFromResources(@NonNull String fileName) {
    InputStream inputStream
    = getClass().getClassLoader().getResourceAsStream(fileName);
    BufferedReader bufferedReader
    = new BufferedReader(new InputStreamReader(inputStream));
    StringBuilder stringBuilder = new StringBuilder();
    try {
    String buffer;
    while ((buffer = bufferedReader.readLine()) != null) {
    stringBuilder.append(buffer);
    }
    } catch (IOException e) {
    fail(e.getMessage(), e);
    }
    return stringBuilder.toString();
    }
    

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36. Fix Test
    @Before
    public void setUp() throws Exception {
    // abbr.
    dataSource = new RestGitHubDataSource(gitHubService);
    }
    @Test
    public void listRepos() throws Exception {
    List repos = restGitHubDataSource.listRepos("srym")
    .test()
    .await()
    .assertNoErrors()
    .assertComplete()
    .values()
    .get(0);
    assertThat(repos).isNotNull();
    // abbr.
    }
    

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37. Passed!
    

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38. Refactoring
    • TDD is NOT perfect
    • Repeat Write & Test
    

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39. Cons
    • Useless when API changes
    • Takes longer time
    

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40. Pros
    • Quality
    • Relief
    • Takes shorter time in total
    

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41. TDD rocks!
    

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42. Thank You
    

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43. Links
    • https://github.com/srym/Architecture
    • https://github.com/square/okhttp/tree/
    master/mockwebserver
    • http://www.irasutoya.com/
    

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