Clean Architecture & TDD

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

Transcript

1. Clean Architecture & TDD @fushiroyama
2. About Me • Fumihiko Shiroyama • Android App Developer • Unit Test Enthusiast • https://github.com/srym
3. Clean Architecture • Presentation • Domain • Infrastructure
4. TDD • Test Driven Development • Test First • Minimum Implementation • Refactoring
5. TDD is great! because... • Focus on I/O • Less reworking • Force Unit Testing
6. Example • Infrastructure • Remote Data Source • GitHub Information • Local Unit Test
7. Interface public interface RemoteGitHubDataSource { Single<List<Repo>> listRepos(@NonNull String user); }
8. Blank Implementation public class RestGitHubDataSource implements RemoteGitHubDataSource { @Override public Single<List<Repo>> listRepos(@NonNull String user) { return Single.error(new RuntimeException()); } }
9. Blank Implementation public class RestGitHubDataSource implements RemoteGitHubDataSource { @Override public Single<List<Repo>> listRepos(@NonNull String user) { return Single.error(new RuntimeException()); } }
10. Create Test • Mouse over class • Alt + Enter • Create Test
11. Create Test
12. Create Test
13. By the way... • Mouse over class • Shift + Command + T • Choose Test
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! } }
15. Test First @Test public void listRepos() throws Exception { List<Repo> repos = restGitHubDataSource.listRepos("srym") .test() .await() .assertNoErrors() .assertComplete() .values() .get(0); assertThat(repos).isNotNull(); }
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();
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
18. Test Execution (failure) • This of course fails.
19. Minimum Implementation public class RestGitHubDataSource implements RemoteGitHubDataSource { private final GitHubService gitHubService; @Inject public RestGitHubDataSource(GitHubService gitHubService) { this.gitHubService = gitHubService; } @Override public Single<List<Repo>> listRepos(@NonNull String user) { return gitHubService.listRepos(user); } }
20. Minimum Implementation public class RestGitHubDataSource implements RemoteGitHubDataSource { private final GitHubService gitHubService; @Inject public RestGitHubDataSource(GitHubService gitHubService) { this.gitHubService = gitHubService; } @Override public Single<List<Repo>> listRepos(@NonNull String user) { return gitHubService.listRepos(user); } }
21. Minimum Implementation public class RestGitHubDataSource implements RemoteGitHubDataSource { private final GitHubService gitHubService; @Inject public RestGitHubDataSource(GitHubService gitHubService) { this.gitHubService = gitHubService; } @Override public Single<List<Repo>> listRepos(@NonNull String user) { return gitHubService.listRepos(user); } }
22. But wait... • This is Local Unit Test • Mock data? Hmm.
23. MockWebServer
24. MockWebServer • Provided by OkHttp • Full HTTP Stack • Can test REAL response
25. MockWebServer private final MockWebServer mockWebServer = new MockWebServer();
26. MockWebServer Dispatcher dispatcher = new Dispatcher() { @Override public MockResponse dispatch(RecordedRequest request) throws InterruptedException { return new MockResponse().setResponseCode(404); } }; mockWebServer.setDispatcher(dispatcher); mockWebServer.start();
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); }
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); }
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); }
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
31. MockWebServer Retrofit retrofit = new Retrofit.Builder() .baseUrl(mockWebServer.url("")) .addCallAdapterFactory(RxJava2CallAdapterFactory.create()) .addConverterFactory(GsonConverterFactory.create()) .build(); GitHubService gitHubService = retrofit.create(GitHubService.class);
32. MockWebServer Retrofit retrofit = new Retrofit.Builder() .baseUrl(mockWebServer.url("")) .addCallAdapterFactory(RxJava2CallAdapterFactory.create()) .addConverterFactory(GsonConverterFactory.create()) .build(); GitHubService gitHubService = retrofit.create(GitHubService.class);
33. Prepare Data • Curl • Postman curl https://api.github.com/users/srym/repos > users_repos.json
34. Prepare Data • Put it test/resources
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(); }
36. Fix Test @Before public void setUp() throws Exception { // abbr. dataSource = new RestGitHubDataSource(gitHubService); } @Test public void listRepos() throws Exception { List<Repo> repos = restGitHubDataSource.listRepos("srym") .test() .await() .assertNoErrors() .assertComplete() .values() .get(0); assertThat(repos).isNotNull(); // abbr. }
37. Passed!
38. Refactoring • TDD is NOT perfect • Repeat Write & Test
39. Cons • Useless when API changes • Takes longer time
40. Pros • Quality • Relief • Takes shorter time in total
41. TDD rocks!
42. Thank You
43. Links • https://github.com/srym/Architecture • https://github.com/square/okhttp/tree/ master/mockwebserver • http://www.irasutoya.com/