I See Continuous Improvement

How setting up CI for your Android projects leads to continuous improvement of the codebase.

Transcript

1. I see Continuous Improvement
   Oubai Abbasi and Ahmed El-Helw
   

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2. How do we know the stability
   of a given build?
   

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3. How do we maintain code
   quality as the team grows?
   

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4. How do we quickly find bugs
   before they make their way into
   production?
   

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5. How do we make builds
   available more widely?
   

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6. How do we uncover hidden
   changes in our apps?
   

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7. Why?
   • Maintain a stylistically consistent code base
   
   • Catch common bugs and design flaws early on
   
   • Encourage a test driven culture
   
   • Build trust in the code quality
   

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9. Static Analysis Tools
   Catching issues early
   

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10. “Checkstyle is a development tool to help programmers write Java
    code that adheres to a coding standard.”
    

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11. “It automates the process of checking Java code to spare
    humans of this boring (but important) task. This makes it
    ideal for projects that want to enforce a coding standard.”
    

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12. package ae.droidcon.checkstyle;
    class Example {
    static int add(int first, int second) {
    return first + second;
    }
    }
    

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13. [ant:checkstyle] [WARN] ~/code/experimentation/src/
    main/java/ae/droidcon/checkstyle/Example.java:5:1:
    Line contains a tab character. [FileTabCharacter]
    

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15. package ae.droidcon.checkstyle;
    public class Example< T> {
    }
    

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16. [ant:checkstyle] [WARN] ~/code/experimentation/src/
    main/java/ae/droidcon/checkstyle/Example.java:3:32:
    GenericWhitespace '<' is followed by whitespace.
    [GenericWhitespace]
    

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17. package ae.droidcon.checkstyle;
    class Example {
    static void awesome (int a, int b) {
    System.out.println(a + ", " + b);
    }
    }
    

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18. [ant:checkstyle] [WARN] ~/code/experimentation/src/
    main/java/ae/droidcon/checkstyle/Example.java:4:23:
    '(' is preceded with whitespace. [MethodParamPad]
    

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19. • Avoid import java.util.*;
    • Import order
    • Modifier order
    • Unnecessary parentheses
    Other Stylistic Issues
    

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20. “It can find class design problems, method design
    problems.”
    

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21. class Example {
    int useless(int value) {
    value *= 2;
    return value;
    }
    }
    

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22. [ant:checkstyle] [WARN] ~/code/experimentation/src/
    main/java/ae/droidcon/checkstyle/Example.java:5:11:
    Assignment of parameter 'value' is not allowed.
    [ParameterAssignment]
    

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23. package ae.droidcon.checkstyle;
    class Example {
    void play() {
    int fantasy = 7;
    int offset = 0;
    System.out.println(fantasy + offset);
    offset += 3;
    System.out.println(fantasy + offset);
    }
    }
    

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24. [ant:checkstyle] [WARN] ~/code/experimentation/src/
    main/java/ae/droidcon/checkstyle/Example.java:5:9:
    Variable 'fantasy' should be declared final.
    [FinalLocalVariable]
    

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25. package ae.droidcon.checkstyle;
    class Util {
    static void op() {}
    static void secondOp() {}
    }
    

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26. [ant:checkstyle] [WARN] ~/code/experimentation/src/
    main/java/ae/droidcon/checkstyle/Util.java:3:1:
    Utility classes should not have a public or default
    constructor. [HideUtilityClassConstructor]
    

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27. Lint
    Photo by Andrew Neel on Unsplash
    

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28. object Caller {
    fun whoYouGonnaCall(context: Context) {
    val intent = Intent(Intent.ACTION_CALL,
    Uri.parse("tel:" + "GHOSTBUSTERS"))
    context.startActivity(intent)
    }
    }
    

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29. ~/code/experiments/app/src/main/kotlin/ae/droidcon/
    lint/Caller.kt:12: Error: Missing permissions
    required by intent Intent.ACTION_CALL:
    android.permission.CALL_PHONE [MissingPermission]
    context.startActivity(intent)
    

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30. class BoringActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.demo)
    val button: ImageButton = findViewById(R.id.button)
    button.setOnClickListener { }
    }
    }
    

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31. ~/code/experiments/app/src/main/java/ae/droidcon/lint/
    BoringActivity.kt:14: Error: Unexpected implicit cast to
    ImageButton: layout tag was Button [WrongViewCast]
    val button: ImageButton = findViewById(R.id.button)
    

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32. override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.demo)
    val button: Button = findViewById(R.id.button)
    button.setOnClickListener { }
    val drawable = ColorDrawable(
    R.color.accent_material_dark)
    button.background = drawable
    }
    

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33. ~/code/experiments/app/src/main/java/ae/droidcon/
    lint/BoringActivity.kt:20: Error: Call requires API
    level 16 (current min is 14):
    android.view.View#setBackground [NewApi]
    button.background = drawable
    

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34. ~/code/experiments/app/src/main/java/ae/droidcon/
    lint/BoringActivity.kt:19: Error: Should pass
    resolved color instead of resource id here:
    getResources().getColor(R.color.accent_material_dark)
    [ResourceAsColor]
    R.color.accent_material_dark)
    

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35. • WrongThread
    • LongLogTag
    • SQLiteString
    • … and many more
    Additional Checks
    

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37. Error Prone
    

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38. “Using Error Prone to augment the compiler’s type analysis, you can
    catch more mistakes before they cost you time, or end up as bugs in
    production.”
    

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39. public Collection sort(Collection foos) {
    Collections.sort(new ArrayList<>(foos));
    return foos;
    }
    

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40. ~/code/experimentation/src/main/java/ae/droidcon/
    errorprone/Util.java:9: error:
    [UnusedCollectionModifiedInPlace] Collection is
    modified in place, but the result is not used
    Collections.sort(new ArrayList<>(foos));
    ^
    (see http://errorprone.info/bugpattern/
    UnusedCollectionModifiedInPlace)
    

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41. public class Carbon {
    public SimpleDateFormat dating() {
    return new SimpleDateFormat("YYYY-MM-dd");
    }
    }
    

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42. ~/code/experimentation/src/main/java/ae/droidcon/
    errorprone/Carb.java:7: error: [MisusedWeekYear]
    Use of "YYYY" (week year) in a date pattern without
    "ww" (week in year). You probably meant to use
    "yyyy" (year) instead.
    return new SimpleDateFormat("YYYY-MM-dd");
    ^
    (see http://errorprone.info/bugpattern/
    MisusedWeekYear)
    Did you mean 'return new SimpleDateFormat("yyyy-
    MM-dd");'?
    

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43. public class Finder {
    public boolean findWaldo(Set values) {
    return (values.contains(1));
    }
    }
    

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44. ~/code/experimentation/src/main/java/ae/droidcon/
    errorprone/Finder.java:7: error:
    [CollectionIncompatibleType] Argument '1' should
    not be passed to this method; its type int is not
    compatible with its collection's type argument Long
    return (values.contains(1));
    ^
    (see http://errorprone.info/bugpattern/
    CollectionIncompatibleType)
    

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45. public class PostApocolypse {
    private final Set theLastOfUs =
    World.getRemainingHumans();
    private volatile int zombies = 9001;
    public void fightZombies() {
    zombies--;
    }
    }
    

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46. ~/code/experimentation/src/main/java/ae/droidcon/
    errorprone/PostApocolypse.java:9: warning:
    [NonAtomicVolatileUpdate] This update of a volatile
    variable is non-atomic
    zombies--;
    ^
    (see http://errorprone.info/bugpattern/
    NonAtomicVolatileUpdate)
    1 warning
    

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47. public String getFaction(int version) {
    String result;
    switch (version) {
    case FALLOUT_2:
    case FALLOUT_NEW_VEGAS:
    result = "New California Rangers";
    break;
    case FALLOUT_3:
    result = "The Enclave";
    break;
    case FALLOUT_4:
    result = "Institute";
    default:
    result = "War never changes";
    }
    return result;
    }
    

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48. ~/code/experimentation/src/main/java/ae/droidcon/
    errorprone/Fallout.java:17: warning: [FallThrough]
    Execution may fall through from the previous case;
    add a `// fall through` comment before this line if
    it was deliberate
    default:
    ^
    (see http://errorprone.info/bugpattern/
    FallThrough)
    1 warning
    

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49. public class TemplarBase {
    protected Assassin ezio;
    public Creed getCreed() {
    return ezio.getCreed();
    }
    }
    public class TemplarCastle extends TemplarBase {
    protected Assassin ezio;
    }
    

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50. public class TemplarBase {
    protected Assassin ezio;
    public Creed getCreed() {
    return ezio.getCreed();
    }
    }
    public class TemplarCastle extends TemplarBase {
    protected Assassin ezio;
    }
    

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51. ~/code/experimentation/src/main/java/ae/droidcon/
    errorprone/TemplarCastle.java:4: warning:
    [HidingField] Hiding fields of superclasses may
    cause confusion and errors. This field is hiding a
    field of the same name in superclass: TemplarBase
    protected Assassin ezio;
    ^
    (see http://errorprone.info/bugpattern/
    HidingField)
    1 warning
    

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52. • MissingOverride
    • ClassCanBeStatic
    • RemoveUnusedImports
    • SelfAssignment
    Additional Checks
    

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53. • InsecureCryptoUsage
    • FragmentInjection
    • UseBinds
    Security/Perf Checks
    

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54. Infer
    

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55. class Persona {
    private final Mementos mementos = new Mementos();
    Shadow getShadowForPerson(String person) {
    if (mementos.hasShadowFor(person)) {
    return new Shadow(person);
    }
    return null;
    }
    void destroyShadow(String person) {
    final Shadow shadow = getShadowForPerson(person);
    shadow.unshadow();
    }
    }
    

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56. class Persona {
    private final Mementos mementos = new Mementos();
    Shadow getShadowForPerson(String person) {
    if (mementos.hasShadowFor(person)) {
    return new Shadow(person);
    }
    return null;
    }
    void destroyShadow(String person) {
    final Shadow shadow = getShadowForPerson(person);
    shadow.unshadow();
    }
    }
    

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57. Found 1 issue
    Persona.java:13: error: NULL_DEREFERENCE
    object `shadow` last assigned on line 12 could be
    null and is dereferenced at line 13.
    11. void destroyShadow(String person) {
    12. final Shadow shadow =
    getShadowForPerson(person);
    13. > shadow.unshadow();
    14. }
    15. }
    

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58. • Context leaks
    • Resource leaks
    • Unsafe @GuardedBy access
    Additional Checks
    

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60. Testing
    

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61. How to UI test with
    network calls
    

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62. Hitting the real APIs
    • Unreliable
    
    • Can’t test edge cases
    
    • How to test payment related scenarios
    

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63. Hitting the real APIs
    • Unreliable
    
    • Can’t test edge cases
    
    • How to test payment related scenarios
    

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64. Building a mock interface
    •Reliable
    
    •Requires more coding,
    maintenance and testing
    

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65. Building a mock interface
    •Reliable
    
    •Requires more coding,
    maintenance and testing
    

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66. Mock web server
    •No extra code
    
    •Still hard to maintain and prepare
    

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67. class RecordCallsInterceptor constructor(context: Context, val gson: Gson) : Interceptor {
    ...
    override fun intercept(chain: Interceptor.Chain): Response {
    val request = chain.request()
    val response = chain.proceed(request)
    ...
    val recordModel = ApiRecordModel(
    request = ApiRecordRequestModel(
    path = request.url().encodedPath(),
    method = request.method(),
    headers = requestHeaders,
    body = requestBody
    ),
    response = ApiRecordResponseModel(
    code = response.code(),
    headers = responseHeaders,
    body = responseBody
    )
    )
    ...
    dumpToServer(recordModel)
    return response
    }
    }
    

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68. class RecordCallsInterceptor constructor(context: Context, val gson: Gson) : Interceptor {
    ...
    override fun intercept(chain: Interceptor.Chain): Response {
    val request = chain.request()
    val response = chain.proceed(request)
    ...
    val recordModel = ApiRecordModel(
    request = ApiRecordRequestModel(
    path = request.url().encodedPath(),
    method = request.method(),
    headers = requestHeaders,
    body = requestBody
    ),
    response = ApiRecordResponseModel(
    code = response.code(),
    headers = responseHeaders,
    body = responseBody
    )
    )
    ...
    dumpToServer(recordModel)
    return response
    }
    }
    

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69. class RecordCallsInterceptor constructor(context: Context, val gson: Gson) : Interceptor {
    ...
    override fun intercept(chain: Interceptor.Chain): Response {
    val request = chain.request()
    val response = chain.proceed(request)
    ...
    val recordModel = ApiRecordModel(
    request = ApiRecordRequestModel(
    path = request.url().encodedPath(),
    method = request.method(),
    headers = requestHeaders,
    body = requestBody
    ),
    response = ApiRecordResponseModel(
    code = response.code(),
    headers = responseHeaders,
    body = responseBody
    )
    )
    ...
    dumpToServer(recordModel)
    return response
    }
    }
    

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70. class RecordCallsInterceptor constructor(context: Context, val gson: Gson) : Interceptor {
    ...
    override fun intercept(chain: Interceptor.Chain): Response {
    val request = chain.request()
    val response = chain.proceed(request)
    ...
    val recordModel = ApiRecordModel(
    request = ApiRecordRequestModel(
    path = request.url().encodedPath(),
    method = request.method(),
    headers = requestHeaders,
    body = requestBody
    ),
    response = ApiRecordResponseModel(
    code = response.code(),
    headers = responseHeaders,
    body = responseBody
    )
    )
    ...
    dumpToServer(recordModel)
    return response
    }
    }
    

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71. class RecordCallsInterceptor constructor(context: Context, val gson: Gson) : Interceptor {
    ...
    override fun intercept(chain: Interceptor.Chain): Response {
    val request = chain.request()
    val response = chain.proceed(request)
    ...
    val recordModel = ApiRecordModel(
    request = ApiRecordRequestModel(
    path = request.url().encodedPath(),
    method = request.method(),
    headers = requestHeaders,
    body = requestBody
    ),
    response = ApiRecordResponseModel(
    code = response.code(),
    headers = responseHeaders,
    body = responseBody
    )
    )
    ...
    dumpToServer(recordModel)
    return response
    }
    }
    

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72. What do we do with dumped
    requests?
    

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73. We save them as a Postman Collection
    

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74. We save them as a Postman Collection
    • Nice GUI
    
    • Easy to edit responses and search requests
    
    • Supports placeholders for path, headers or body
    

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75. Now what?
    

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76. @Test
    public void loginTest_success() {
    mount("defaultCollection");
    onView(withId(R.id.email)).perform(typeText("test@email.com"));
    onView(withId(R.id.edt_password)).perform(typeText("Password"), closeSoftKeyboard());
    onView(withId(R.id.btn_login_with_fb)).perform(click());
    }
    

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77. @Test
    public void loginTest_success() {
    mount("defaultCollection");
    onView(withId(R.id.email)).perform(typeText("test@email.com"));
    onView(withId(R.id.password)).perform(typeText("Password"), closeSoftKeyboard());
    onView(withId(R.id.btn_login)).perform(click());
    }
    

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78. @Test
    public void loginTest_success() {
    mount("defaultCollection");
    onView(withId(R.id.email)).perform(typeText("test@email.com"));
    onView(withId(R.id.edt_password)).perform(typeText("Password"), closeSoftKeyboard());
    onView(withId(R.id.btn_login_with_fb)).perform(click());
    }
    

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79. fun mount(collectionName: String, fileName: String) {
    cachedCollections[collectionName] = file.item.firstOrNull {
    collection -> collection.name==collectionName
    }?: throw IllegalArgumentException("Collection not found: $collectionName")
    }
    

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80. fun mount(collectionName: String, fileName: String) {
    val file = PostmanLoader.load(fileName)
    cachedCollections[collectionName] = file.item.firstOrNull {
    collection -> collection.name == collectionName
    }?: throw IllegalArgumentException("Collection not found: $collectionName")
    }
    

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81. fun mount(collectionName: String, fileName: String) {
    val file = PostmanLoader.load(fileName)
    cachedCollections[collectionName] = file.item.firstOrNull {
    collection -> collection.name == collectionName
    }?: throw IllegalArgumentException("Collection not found: $collectionName")
    }
    

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82. MockWebServer().apply {
    setDispatcher(object : Dispatcher() {
    override fun dispatch(request: RecordedRequest): MockResponse {
    return mountedCollections
    .firstOrNull { requestsMatch(request, it.request) }?.let {
    createResponseFromPostman(it.response[0])
    } ?: MockResponse().apply { setResponseCode(404) }
    }
    })
    

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83. MockWebServer().apply {
    setDispatcher(object : Dispatcher() {
    override fun dispatch(request: RecordedRequest): MockResponse {
    return mountedCollections
    .firstOrNull { requestsMatch(request, it.request) }?.let {
    createResponseFromPostman(it.response[0])
    } ?: MockResponse().apply { setResponseCode(404) }
    }
    })
    

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84. MockWebServer().apply {
    setDispatcher(object : Dispatcher() {
    override fun dispatch(request: RecordedRequest): MockResponse {
    return mountedCollections
    .firstOrNull { requestsMatch(request, it.request) }?.let {
    createResponseFromPostman(it.response[0])
    } ?: MockResponse().apply { setResponseCode(404) }
    }
    })
    

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85. MockWebServer().apply {
    setDispatcher(object : Dispatcher() {
    override fun dispatch(request: RecordedRequest): MockResponse {
    return mountedCollections
    .firstOrNull { requestsMatch(request, it.request) }?.let {
    createResponseFromPostman(it.response[0])
    } ?: MockResponse().apply { setResponseCode(404) }
    }
    })
    

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86. How to confirm the UI looks
    right?
    

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87. @Test
    public void loginTest_success() {
    mount("defaultCollection");
    screenshot("loginTest", "success", "emptyFields", lang);
    onView(withId(R.id.email)).perform(typeText("test@email.com"));
    onView(withId(R.id.edt_password)).perform(typeText("Password"), closeSoftKeyboard());
    screenshot("loginTest", "success", "filledFields", lang);
    onView(withId(R.id.btn_login_with_fb)).perform(click());
    screenshot("loginTest", "success", "loading", lang);
    }
    

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88. @Test
    public void loginTest_success() {
    mount("defaultCollection");
    screenshot("loginTest", "success", "emptyFields", lang);
    onView(withId(R.id.email)).perform(typeText("test@email.com"));
    onView(withId(R.id.edt_password)).perform(typeText("Password"), closeSoftKeyboard());
    screenshot("loginTest", "success", "filledFields", lang);
    onView(withId(R.id.btn_login_with_fb)).perform(click());
    screenshot("loginTest", "success", "loading", lang);
    }
    

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89. What to do with screenshot?
    • Upload them to your server
    
    • Tag them with configuration, test,
    scenario, date
    
    • Run image diffing (ie: http://www.imagemagick.org/
    Usage/compare/)
    
    • Flag different/new screenshots for manual
    verification
    

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90. Making it cross platform
    • Share API data
    
    • Run a python mock server instead of OkHttp
    
    • Share screenshot diff-ing logic/UI
    

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91. Hidden Changes
    

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92. Photo from LifeWithCats
    

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93. Permissions
    

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94. aapt d permissions ./app/build/outputs/apk/debug/app-debug.apk
    uses-permission: name='android.permission.INTERNET'
    uses-permission: name='android.permission.WRITE_EXTERNAL_STORAGE'
    uses-permission: name='android.permission.ACCESS_NETWORK_STATE'
    uses-permission: name='android.permission.WAKE_LOCK'
    uses-permission: name='android.permission.READ_EXTERNAL_STORAGE'
    

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95. dependencies {
    implementation deps.helpbug.helpbug
    // more dependencies
    }
    

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96. aapt d permissions ./app/build/outputs/apk/debug/app-debug.apk
    

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97. › diff before after
    6a7,9
    > uses-permission: name='android.permission.ACCESS_WIFI_STATE'
    > uses-permission: name='android.permission.RECORD_AUDIO'
    > uses-permission: name='android.permission.MODIFY_AUDIO_SETTINGS'
    Picture from principedifino
    

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98. Method Count
    

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99. > Task :app:countDebugDexMethods
    Total methods in app-debug.apk: 52673 (80.37% used)
    Total fields in app-debug.apk: 30053 (45.86% used)
    Total classes in app-debug.apk: 6962 (10.62% used)
    Methods remaining in app-debug.apk: 12862
    Fields remaining in app-debug.apk: 35482
    Classes remaining in app-debug.apk: 58573
    

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100. View Slide

101. dependencies {
     implementation deps.helpbug.helpbug
     // more dependencies
     }
     

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102. > Task :app:countDebugDexMethods
     Total methods in app-debug.apk: 69802 (106.51% used)
     Total fields in app-debug.apk: 42438 (64.76% used)
     Total classes in app-debug.apk: 9291 (14.18% used)
     Methods remaining in app-debug.apk: 0
     Fields remaining in app-debug.apk: 23097
     Classes remaining in app-debug.apk: 56244
     

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103. Delta methods: +17129
     Delta fields: +12385
     Delta classes: +2329
     

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104. APK Size
     

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105. What else can we do?
     •Upload apk to S3 bucket for internal
     distribution
     
     •Automatically upload builds to
     Google Play
     
     •Post on slack about new builds
     

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106. lane :alpha do
     gradle(task: "clean assembleDebug test android")
     aws_s3
     slack({
     message: "new version uploaded to S3",
     channel: “#qa"
     })
     end
     

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107. lane :alpha do
     gradle(task: "clean assembleDebug test android")
     aws_s3
     slack({
     message: "new version uploaded to S3",
     channel: “#qa"
     })
     end
     

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108. lane :alpha do
     gradle(task: "clean assembleDebug test android")
     aws_s3
     slack({
     message: "new version uploaded to S3",
     channel: “#qa"
     })
     end
     

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109. lane :alpha do
     gradle(task: "clean assembleDebug test android")
     aws_s3
     slack({
     message: "new version uploaded to S3",
     channel: “#qa"
     })
     end
     

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110. lane :alpha do
     gradle(task: "clean assembleDebug test android")
     aws_s3
     slack({
     message: "new version uploaded to S3",
     channel: “#qa"
     })
     end
     

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111. lane :release do
     gradle(task: "clean assembleRelease test android")
     supply
     slack({
     message: "new version released",
     channel: “#announcements"
     })
     end
     

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112. lane :release do
     gradle(task: "clean assembleRelease test android")
     supply
     slack({
     message: "new version released",
     channel: “#announcements"
     })
     end
     

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113. Code Coverage
     

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118. Photo by Robert Zunikoff on Unsplash
     

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119. Photo by Annie Spratt on Unsplash
     Where?
     

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120. Compilation time
     Pull request time
     Commit time
     Post-commit time
     Photo by Ales Krivec on Unsplash
     

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121. Photo by Evan Kirby on Unsplash
     Gotchas
     • Flaky Tests
     • Tool version updates
     • Unstable environment
     • Crashing tests
     

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122. Test Orchestrator
     

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123. • Invest in improving build times
     • Set up static analysis tools
     • Optimize for code quality and
     stability
     Summary
     

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125. Photo by Bryan Minear on Unsplash
     

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126. References
     • https://speakerdeck.com/kaskasi/i-am-on-a-fastlane-to-hell
     
     • https://medium.com/square-corner-blog/surfacing-hidden-
     change-to-pull-requests-6a371266e479
     
     • https://github.com/KeepSafe/dexcount-gradle-plugin
     
     • https://github.com/JakeWharton/dex-method-list
     
     • http://www.imagemagick.org/Usage/compare/
     
     • https://android.github.io/kotlin-guides/interop.html
     

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