Diving into the inner workings of OkReplay

In this talk we covered the internals of the OkReplay library for recording and replaying Espresso tests.

Transcript

1. Diving into the inner
   workings of OkReplay
   FELIPE LIMA / @FELIPECSL / MAY 17, 2018 / DROIDCHELLA
   

   View Slide

2. WHAT’S OKREPLAY?
   

   View Slide

3. Story time!
   

   View Slide

4. WAIT, BUT WHY?
   

   View Slide

5. Timeline
   VCR
   2010
   

   View Slide

6. Timeline
   VCR BETAMAX
   2010 2011
   

   View Slide

7. Timeline
   VCR BETAMAX OKREPLAY
   2010 2011 2017
   

   View Slide

8. Test Pyramid
   

   View Slide

9. Test Pyramid
   

   View Slide

10. ARCHITECTURE
    

    View Slide

11. • okreplay-core
    • okreplay-junit
    • okreplay-espresso
    • okreplay-gradle-plugin
    • okreplay-sample
    • okreplay-noop
    • okreplay-tests
    Modular architecture
    

    View Slide

12. • Yaml file where a list of http “interactions” is recorded
    • Each test method corresponds to a tape file
    • Interactions are recorded in request-response pairs
    • Includes method, URL, status, headers and response body
    • Modes: read-only, read-write, write-only, etc.
    • Read from instrumentation APK “assets” directory
    • Writes to device’s external storage directory
    Tape
    WHERE INTERACTIONS HAPPEN
    

    View Slide

13. Tape file !tape
    name: test league
    interactions:
    - recorded: 2017-07-31T03:46:40.477Z
    request:
    method: GET
    uri: http://elifut.com/nations.json
    response:
    status: 200
    headers:
    Cache-Control: max-age=0, private, must-revalidate
    Connection: keep-alive
    Content-Type: application/json; charset=utf-8
    Date: Mon, 31 Jul 2017 03:47:07 GMT
    Server: nginx/1.10.3 + Phusion Passenger 5.1.5
    Status: 200 OK
    Transfer-Encoding: chunked
    X-Content-Type-Options: nosniff
    X-Frame-Options: SAMEORIGIN
    X-Powered-By: Phusion Passenger 5.1.5
    X-Runtime: '0.012716'
    X-XSS-Protection: 1; mode=block
    body: ''
    

    View Slide

14. Tape class hierarchy
    Tape
    Concrete class
    Abstract class
    Interface
    

    View Slide

15. Tape class hierarchy
    Tape
    MemoryTape
    Concrete class
    Abstract class
    Interface
    

    View Slide

16. Tape class hierarchy
    Tape
    MemoryTape
    YamlTape
    Concrete class
    Abstract class
    Interface
    

    View Slide

17. Core
    OKHTTP INTERCEPTOR
    @Override
    public Response intercept(Chain chain) {
    Request request = chain.request();
    if (isRunning) {
    Request recordedRequest = OkHttpRequestAdapter.adapt(request);
    if (tape.isReadable() && tape.seek(recordedRequest)) {
    return replayTape(request, tape, recordedRequest);
    } else {
    return recordResponse(chain, request, tape, recordedRequest);
    }
    } else {
    return chain.proceed(request);
    }
    }
    

    View Slide

18. Core
    OKHTTP INTERCEPTOR
    @Override
    public Response intercept(Chain chain) {
    Request request = chain.request();
    if (isRunning) {
    Request recordedRequest = OkHttpRequestAdapter.adapt(request);
    if (tape.isReadable() && tape.seek(recordedRequest)) {
    return replayTape(request, tape, recordedRequest);
    } else {
    return recordResponse(chain, request, tape, recordedRequest);
    }
    } else {
    return chain.proceed(request);
    }
    }
    

    View Slide

19. Core
    OKHTTP INTERCEPTOR
    @Override
    public Response intercept(Chain chain) {
    Request request = chain.request();
    if (isRunning) {
    Request recordedRequest = OkHttpRequestAdapter.adapt(request);
    if (tape.isReadable() && tape.seek(recordedRequest)) {
    return replayTape(request, tape, recordedRequest);
    } else {
    return recordResponse(chain, request, tape, recordedRequest);
    }
    } else {
    return chain.proceed(request);
    }
    }
    

    View Slide

20. Core
    OKHTTP INTERCEPTOR
    @Override
    public Response intercept(Chain chain) {
    Request request = chain.request();
    if (isRunning) {
    Request recordedRequest = OkHttpRequestAdapter.adapt(request);
    if (tape.isReadable() && tape.seek(recordedRequest)) {
    return replayTape(request, tape, recordedRequest);
    } else {
    return recordResponse(chain, request, tape, recordedRequest);
    }
    } else {
    return chain.proceed(request);
    }
    }
    

    View Slide

21. Core
    OKHTTP INTERCEPTOR
    @Override
    public Response intercept(Chain chain) {
    Request request = chain.request();
    if (isRunning) {
    Request recordedRequest = OkHttpRequestAdapter.adapt(request);
    if (tape.isReadable() && tape.seek(recordedRequest)) {
    return replayTape(request, tape, recordedRequest);
    } else {
    return recordResponse(chain, request, tape, recordedRequest);
    }
    } else {
    return chain.proceed(request);
    }
    }
    

    View Slide

22. Core
    OKHTTP INTERCEPTOR
    @Override
    public Response intercept(Chain chain) {
    Request request = chain.request();
    if (isRunning) {
    Request recordedRequest = OkHttpRequestAdapter.adapt(request);
    if (tape.isReadable() && tape.seek(recordedRequest)) {
    return replayTape(request, tape, recordedRequest);
    } else {
    return recordResponse(chain, request, tape, recordedRequest);
    }
    } else {
    return chain.proceed(request);
    }
    }
    

    View Slide

23. Replaying Responses
    private okhttp3.Response replayResponse(
    okhttp3.Request request,
    Tape tape,
    Request recordedRequest
    ) {
    Response recordedResponse = tape.play(recordedRequest);
    okhttp3.Response okhttpResponse =
    OkHttpResponseAdapter.adapt(request, recordedResponse);
    okhttpResponse = setOkReplayHeader(okhttpResponse, "PLAY");
    okhttpResponse = setViaHeader(okhttpResponse);
    return okhttpResponse;
    }
    

    View Slide

24. Replaying Responses
    abstract class MemoryTape implements Tape {
    @Override public Response play(final Request request) {
    if (mode.isSequential()) {
    Integer nextIndex = orderedIndex.getAndIncrement();
    RecordedInteraction nextInteraction = interactions.get(nextIndex).toImmutable();
    return nextInteraction.response();
    } else {
    int position = findMatch(request);
    if (position < 0) {
    throw new IllegalStateException("no matching recording found");
    } else {
    return interactions.get(position).toImmutable().response();
    }
    }
    }
    }
    

    View Slide

25. Replaying Responses
    abstract class MemoryTape implements Tape {
    @Override public Response play(final Request request) {
    if (mode.isSequential()) {
    Integer nextIndex = orderedIndex.getAndIncrement();
    RecordedInteraction nextInteraction = interactions.get(nextIndex).toImmutable();
    return nextInteraction.response();
    } else {
    int position = findMatch(request);
    if (position < 0) {
    throw new IllegalStateException("no matching recording found");
    } else {
    return interactions.get(position).toImmutable().response();
    }
    }
    }
    }
    

    View Slide

26. Replaying Responses
    abstract class MemoryTape implements Tape {
    @Override public Response play(final Request request) {
    if (mode.isSequential()) {
    Integer nextIndex = orderedIndex.getAndIncrement();
    RecordedInteraction nextInteraction = interactions.get(nextIndex).toImmutable();
    return nextInteraction.response();
    } else {
    int position = findMatch(request);
    if (position < 0) {
    throw new IllegalStateException("no matching recording found");
    } else {
    return interactions.get(position).toImmutable().response();
    }
    }
    }

    }
    

    View Slide

27. OkReplay Annotation
    @Retention(AnnotationRetention.RUNTIME)
    @Target(AnnotationTarget.FUNCTION,
    AnnotationTarget.CLASS,
    AnnotationTarget.FILE)
    annotation class OkReplay(
    val tape: String = "",
    val mode: TapeMode = TapeMode.UNDEFINED,
    val match: Array = []
    )
    

    View Slide

28. Tape Modes
    public enum TapeMode {
    UNDEFINED,
    READ_WRITE,
    READ_ONLY,
    READ_ONLY_QUIET,
    READ_SEQUENTIAL,
    WRITE_ONLY,
    WRITE_SEQUENTIAL;
    }
    

    View Slide

29. x
    Match Rules
    public enum MatchRules implements MatchRule {
    method {
    @Override public boolean isMatch(Request a, Request b) {
    return a.method().equalsIgnoreCase(b.method());
    }
    }, uri {
    @Override public boolean isMatch(Request a, Request b) {
    return a.url().equals(b.url());
    }
    }, host {
    @Override public boolean isMatch(Request a, Request b) {
    return a.url().url().getHost().equals(b.url().url().getHost());
    }
    }, path {
    @Override public boolean isMatch(Request a, Request b) {
    return a.url().url().getPath().equals(b.url().url().getPath());
    }
    }, port {
    @Override public boolean isMatch(Request a, Request b) {
    return a.url().url().getPort() == b.url().url().getPort();
    }
    }
    }
    

    View Slide

30. Test Rule class RecorderRule(
    configuration: OkReplayConfig
    ) : Recorder(configuration), TestRule {
    override fun apply(statement: Statement, description: Description): Statement {
    val annotation = description.getAnnotation(OkReplay::class.java)
    if (annotation != null) {
    return object : Statement() {
    override fun evaluate() {
    try {
    val tapeName = annotation.tape
    val tapeMode = annotation.mode
    val matchRules = annotation.match
    val matchRule = ComposedMatchRule.of(*matchRules)
    start(tapeName, tapeMode.toOptional(), matchRule)
    statement.evaluate()
    } catch (e: Exception) {
    throw e
    } finally {
    stop()
    }
    }
    }
    } else {
    return statement
    }
    }
    }
    

    View Slide

31. Test Rule class RecorderRule(
    configuration: OkReplayConfig
    ) : Recorder(configuration), TestRule {
    override fun apply(statement: Statement, description: Description): Statement {
    val annotation = description.getAnnotation(OkReplay::class.java)
    if (annotation != null) {
    return object : Statement() {
    override fun evaluate() {
    try {
    val tapeName = annotation.tape
    val tapeMode = annotation.mode
    val matchRules = annotation.match
    val matchRule = ComposedMatchRule.of(*matchRules)
    start(tapeName, tapeMode.toOptional(), matchRule)
    statement.evaluate()
    } catch (e: Exception) {
    throw e
    } finally {
    stop()
    }
    }
    }
    } else {
    return statement
    }
    }
    }
    

    View Slide

32. Test Rule class RecorderRule(
    configuration: OkReplayConfig
    ) : Recorder(configuration), TestRule {
    override fun apply(statement: Statement, description: Description): Statement {
    val annotation = description.getAnnotation(OkReplay::class.java)
    if (annotation != null) {
    return object : Statement() {
    override fun evaluate() {
    try {
    val tapeName = annotation.tape
    val tapeMode = annotation.mode
    val matchRules = annotation.match
    val matchRule = ComposedMatchRule.of(*matchRules)
    start(tapeName, tapeMode.toOptional(), matchRule)
    statement.evaluate()
    } catch (e: Exception) {
    throw e
    } finally {
    stop()
    }
    }
    }
    } else {
    return statement
    }
    }
    }
    

    View Slide

33. Test Rule class RecorderRule(
    configuration: OkReplayConfig
    ) : Recorder(configuration), TestRule {
    override fun apply(statement: Statement, description: Description): Statement {
    val annotation = description.getAnnotation(OkReplay::class.java)
    if (annotation != null) {
    return object : Statement() {
    override fun evaluate() {
    try {
    val tapeName = annotation.tape
    val tapeMode = annotation.mode
    val matchRules = annotation.match
    val matchRule = ComposedMatchRule.of(*matchRules)
    start(tapeName, tapeMode.toOptional(), matchRule)
    statement.evaluate()
    } catch (e: Exception) {
    throw e
    } finally {
    stop()
    }
    }
    }
    } else {
    return statement
    }
    }
    }
    

    View Slide

34. Test Rule class RecorderRule(
    configuration: OkReplayConfig
    ) : Recorder(configuration), TestRule {
    override fun apply(statement: Statement, description: Description): Statement {
    val annotation = description.getAnnotation(OkReplay::class.java)
    if (annotation != null) {
    return object : Statement() {
    override fun evaluate() {
    try {
    val tapeName = annotation.tape
    val tapeMode = annotation.mode
    val matchRules = annotation.match
    val matchRule = ComposedMatchRule.of(*matchRules)
    start(tapeName, tapeMode.toOptional(), matchRule)
    statement.evaluate()
    } catch (e: Exception) {
    throw e
    } finally {
    stop()
    }
    }
    }
    } else {
    return statement
    }
    }
    }
    

    View Slide

35. Test Rule class RecorderRule(
    configuration: OkReplayConfig
    ) : Recorder(configuration), TestRule {
    override fun apply(statement: Statement, description: Description): Statement {
    val annotation = description.getAnnotation(OkReplay::class.java)
    if (annotation != null) {
    return object : Statement() {
    override fun evaluate() {
    try {
    val tapeName = annotation.tape
    val tapeMode = annotation.mode
    val matchRules = annotation.match
    val matchRule = ComposedMatchRule.of(*matchRules)
    start(tapeName, tapeMode.toOptional(), matchRule)
    statement.evaluate()
    } catch (e: Exception) {
    throw e
    } finally {
    stop()
    }
    }
    }
    } else {
    return statement
    }
    }
    }
    

    View Slide

36. Recorder Rule
    STARTING THE TAPE
    public class Recorder {
    public void start(
    String tapeName,
    Optional mode,
    Optional matchRule
    ) {
    tape = getTapeLoader().loadTape(tapeName);
    tape.setMode(mode.or(configuration.getDefaultMode()));
    tape.setMatchRule(matchRule.or(configuration.getDefaultMatchRule()));
    configuration.interceptor().start(configuration, tape);
    }
    }
    

    View Slide

37. Class hierarchy Message
    Request Response
    RecordedRequest RecordedResponse
    AbstractMessage
    RecordedMessage
    Concrete class
    Abstract class
    Interface
    MAIN ENTITIES
    

    View Slide

38. Usage
    @RunWith(AndroidJUnit4.class)
    public class ExampleInstrumentationTest {
    private final ActivityTestRule activityTestRule =
    new ActivityTestRule<>(MainActivity.class);
    private final OkReplayConfig configuration = new OkReplayConfig.Builder()
    .tapeRoot(new AndroidTapeRoot(getContext(), getClass()))
    .defaultMode(TapeMode.READ_WRITE)
    .interceptor(new OkReplayInterceptor())
    .defaultMatchRules(MatchRules.host, MatchRules.path, MatchRules.method)
    .build();
    @Rule public final TestRule testRule =
    new OkReplayRuleChain(configuration, activityTestRule).get();
    @Test
    @OkReplay
    public void bar() {
    onView(withId(R.id.foo)).perform(click());
    onView(withId(R.id.bar)).check(matches(withText(containsString("bar"))));
    }
    }
    

    View Slide

39. Usage
    @RunWith(AndroidJUnit4.class)
    public class ExampleInstrumentationTest {
    private final ActivityTestRule activityTestRule =
    new ActivityTestRule<>(MainActivity.class);
    private final OkReplayConfig configuration = new OkReplayConfig.Builder()
    .tapeRoot(new AndroidTapeRoot(getContext(), getClass()))
    .defaultMode(TapeMode.READ_WRITE)
    .interceptor(new OkReplayInterceptor())
    .defaultMatchRules(MatchRules.host, MatchRules.path, MatchRules.method)
    .build();
    @Rule public final TestRule testRule =
    new OkReplayRuleChain(configuration, activityTestRule).get();
    @Test
    @OkReplay
    public void bar() {
    onView(withId(R.id.foo)).perform(click());
    onView(withId(R.id.bar)).check(matches(withText(containsString("bar"))));
    }
    }
    

    View Slide

40. Usage
    @RunWith(AndroidJUnit4.class)
    public class ExampleInstrumentationTest {
    private final ActivityTestRule activityTestRule =
    new ActivityTestRule<>(MainActivity.class);
    private final OkReplayConfig configuration = new OkReplayConfig.Builder()
    .tapeRoot(new AndroidTapeRoot(getContext(), getClass()))
    .defaultMode(TapeMode.READ_WRITE)
    .interceptor(new OkReplayInterceptor())
    .defaultMatchRules(MatchRules.host, MatchRules.path, MatchRules.method)
    .build();
    @Rule public final TestRule testRule =
    new OkReplayRuleChain(configuration, activityTestRule).get();
    @Test
    @OkReplay
    public void bar() {
    onView(withId(R.id.foo)).perform(click());
    onView(withId(R.id.bar)).check(matches(withText(containsString("bar"))));
    }
    }
    

    View Slide

41. Usage
    @RunWith(AndroidJUnit4.class)
    public class ExampleInstrumentationTest {
    private final ActivityTestRule activityTestRule =
    new ActivityTestRule<>(MainActivity.class);
    private final OkReplayConfig configuration = new OkReplayConfig.Builder()
    .tapeRoot(new AndroidTapeRoot(getContext(), getClass()))
    .defaultMode(TapeMode.READ_WRITE)
    .interceptor(new OkReplayInterceptor())
    .defaultMatchRules(MatchRules.host, MatchRules.path, MatchRules.method)
    .build();
    @Rule public final TestRule testRule =
    new OkReplayRuleChain(configuration, activityTestRule).get();
    @Test
    @OkReplay
    public void bar() {
    onView(withId(R.id.foo)).perform(click());
    onView(withId(R.id.bar)).check(matches(withText(containsString("bar"))));
    }
    }
    

    View Slide

42. PITFALLS
    

    View Slide

43. • Granting WRITE_EXTERNAL_STORAGE permission
    • Handling secrets
    • Re-recording tapes
    • If your test fails, you’ll need to re-record the tapes
    • Switching between replaying/recording modes
    Pitfalls
    

    View Slide

44. • Writing stable Espresso tests is hard
    • A lot of cool concepts can be brought in from other platforms
    • Naming is also hard
    • Writing stable and reproducible Android UI tests is possible
    Conclusion
    FINAL REMARKS
    

    View Slide

45. QUESTIONS?
    

    View Slide

46. THANKS!
    

    View Slide