droidconuk: tdd android with robolectric

Android Unit Test Frameworkhttp://robolectric.org

@robolectric

Saturday, October 8, 11

Joe Moore@joem

Pivotal Labs@pivotallabs


Disclaimer

I’m mostly a Ruby guy now


Agenda

• Testing Approaches and Alternatives

• How Robolectric works

• How to extend Robolectric


Software consulting company, primarily Ruby on Rails, Android, and iOS

XP, TDD, Pair Programming

SF, NYC, Boulder CO, SingaporeSaturday, October 8, 11

BDD for iOSCedar

JsUnit

We Test StuffGreat Expectations

Jasmine-style assertions for JUnit


java.lang.RuntimeException(“Stub!”)


Google replaced the method bodies in android.jar with:

java.lang.RuntimeException(“Stub!”)


java.lang.RuntimeException: Stub!! at android.content.Context.<init>(Context.java:4)! at android.content.ContextWrapper.<init>(ContextWrapper.java:5)! at android.view.ContextThemeWrapper.<init>(ContextThemeWrapper.java:5)! at android.app.Activity.<init>(Activity.java:6)! at com.pivotallabs.NamesActivity.<init>(NamesActivity.java:9)

Every JUnit Test Fails


Additional Android Testing Challenges

• Many of the classes, methods are final

• Lack of interfaces

• Non public constructors

• Static methods


It’s Getting Better

CalculonA testing DSL for Google Android


How have you been testing?


Android Testing Approaches



• Integration-style




•Library of tested POJO’s





•Mocking framework





•Mocking framework

•F@*K IT!


Why use Robolectric?


Features• FAST!

• Interact with Android code.

• Parsing, loading of layouts, strings.xml, colors.xml, etc.

• State tracking of many Android objects

• Amazing HTTP/API testing

• Wonderful static helpers methods allowing instantiation of privates and other... stuff :)

• Supports Android frameworks like RoboGuice, android-mock, and other Android frameworks.


Instrumentation Tests require dexing, packaging and installation on an emulator or device to run in the Dalvik VM.

vs. Android Instrumentation Tests?Instrumentation Tests are


Robolectric runs in the regular JVM:

No dexing, packaging, deploying, etc.

vs. Android Instrumentation Tests?

FAST


Robolectric lets you:

• Use Ye Olde JUnit

• Iterate quickly

• Test behavior instead of implementation

• Have high test coverage

• Supports the way Android developers are taught to develop (for better or for worse.)


• http://robolectric.org

• http://github.com/pivotal/robolectric/

• http://github.com/pivotal/RobolectricSample

How can I get started?


http://robolectric.org

http://robolectric.org

http://pivotal.github.com/robolectric/index.html

http://pivotal.github.com/robolectric/index.html

http://github.com/pivotal/RobolectricSample

http://github.com/pivotal/RobolectricSample

Writing Tests


Writing TestsTests that reference Android need to be annotated:

@RunWith(RobolectricTestRunner.class)public class MyActivityTest {

@Test! public void shouldDoWizbangFooBar() {...


Writing TestsSometimes you do not even see Robolectric

(Where is Robolectric? Nice and hidden!)

@RunWith(RobolectricTestRunner.class)public class MyActivityTest { private View homeButton; private Activity activity ...

@Test! public void shouldDoWizbangFooBar() { homeButton = activity.findViewById(R.id.home);


...

@Testpublic void logoImageViewShouldUseTheLogoDrawable() {

ImageView logo = (ImageView) activity.findViewById(R.id.logo);// imageView only provides logo.getDrawable();ShadowImageView logoShadow = Robolectric.shadowOf(logo);assertThat(logoShadow.resourceId, equalTo(R.drawable.logo));

}

Writing TestsTalking to Shadows


HTTP Testing

java.lang.RuntimeException: Unexpected call to execute, no pending responses are available. See Robolectric.addPendingResponse().

Request was: GET http://example.com/foo/bar.json?page=28...

Unexpected HTTP Calls Throw Exceptions


http://search.twitter.com/search.atom?q=robolectric&rpp=2

http://search.twitter.com/search.atom?q=robolectric&rpp=2

HTTP TestingHTTP Handling Methods

public class Robolectric


HTTP Testing

new FakeHttpLayer.RequestMatcherBuilder() .host("http://example.com") .path("foo/bar.json") .method("GET") .param("page","28") .header("header1", "someValue");

Robolectric.addHttpResponseRule(requestMatcher, response)


http://example.com

http://example.com

HTTP TestingRobolectric.addHttpResponseRule(requestMatcher, response)

new TestHttpResponse(200, "{ 'jsonObj': {'key': 'value'}");

new TestHttpResponse(200, Fixtures.load(“users.json”);

Verifying that your app can parse API data is a good idea!


HighlightsGetting the Latest...

ShadowAlertDialog.getLatestDialog()ShadowAlertDialog.getLatestAlertDialog()ShadowToast.getLatestToast()

myShadowNotification.getLatestEventInfo()

Robolectric.getShadowApplication().getNextStartedActivity()~ or ~ .getNextStartedService()


HighlightsLoopers, Schedulers

ShadowLooper.getMainLooper()

shadowMainLooper.getScheduler()

Robolectric.pauseMainLooper()

Robolectric.unPauseMainLooper()


How does it work?


Shadow Objects

“Shadow” implementations of Android classes


Shadow Objects


Button(Android)

ShadowButtonmyButton.getText() getText()

text=“Okay”return “Okay”return “Okay”

Shadow Objects


Button(Android)

ShadowButton

myButton.getSomething() getSomething()

Does not implement getSomething()

return null;

Shadow Objects


How does it work?1. Robolectric intercepts the loading of Android

classes under test



classes under test

2. Rewrites the method bodies of Android classes (using javassist)

Shadow Objects



classes under test


3. Binds “shadow objects” to new Android objects

Shadow Objects



classes under test


3. Binds “shadow objects” to new Android objects

4. The modified Android objects then proxy method calls to the shadow objects

Shadow Objects


What About Using “Real” Android Jars?

• Brach on github: “reviscerated”

• Blog article: robolectric.blogspot.com

• It’s hard: hand-building jars, native code, indeterminate expectations.


Where do the Shadow Implementations come From?

Us, and you!

This project is open source and maintained by the Robolectric community.

Please contribute at http://github.com/pivotal/robolectric


Extending Robolectric

Help Robolectric cover moreof Android


Shadow Objects

Shadow inheritance works.

Some shadows are not implemented because most of their functionality is inherited.


Writing Shadow Objects

• @Implements

• @Implementation

• Robolectric.getDefaultShadowClasses()

• __constructor__

• @RealObject


Shadow Objects@Implements

@Implements(View.class)public class ShadowView { ...}


Shadow Objects@Implementation

... @Implementation public int getId() { return this.id; } ...


Shadow ObjectsRobolectric.getDefaultShadowClasses()

return Arrays.asList( ShadowAbsListView.class, ShadowAbsoluteLayout.class, ShadowAbsSeekBar.class, ShadowAbsSpinner.class, ShadowAbstractCursor.class, ShadowActivity.class, ShadowActivityInfo.class, ...


Shadow Objects__constructor__

public class View { public View(Context context) { /* compiled code */ } ...

public class ShadowView { public void __constructor__(Context context) { ... } ...


Shadow Objects@RealObject

@Implements(View.class)public class ShadowView { @RealObject private View realView; ...


Joe Moore@joem

Pivotal Labs@pivotallabs

Thanks!


droidconuk: tdd android with robolectric

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