RobolectricTest Android on the JVM

HELLO!

I am Richard ChangAndroid Engineer in HTC, Movial and VMFiveYou can find me via chiel99 AT gmail.com

Outline● Challenges of Android unit test ● Robolectric● PowerMock● JaCoCo● Reference

Challenges of Android unit test

1. java.lang.RuntimeException(“Stub!”)

Google removed the method body in android.jar

2. Mock everything

Mock framework is great!But mocking every Android framework object exhausts

programmers

3. On Real Device or Emulator

Impact your Continueous Integration (CI) processSLOW, SLOW, SLOW

Robolectric

What is Robolectric?

● An Android unit test framework that let you run your tests on regular JVM

● Start from Xtreme Labs (Acquired by Pivotal Labs)● Open source

Why Robolectric?

● Fast● Run on JVM instead of Dalvik/ART

○ No dexing, packaging, signing, deploying...● Well handled the resources/layout xmls emulation

○ findViewById(R.id.text)● Can be collaborated with other mock frameworks

○ Mockito, PowerMock...

How it works?

● Shadow objects○ Robolectric replaces Android classes so-called Shadows

● Robolectric intercepts the loading of Android classes during testing

Android ImageView

Test codeShadow

ImageView

mImgView.getImageBitmap getImageBitmap

return Bitmapreturn Bitmap

Shadows

How to use Robolectric?

● Build.gradle○ dependencies: testCompile "org.robolectric:robolectric:3.0"

● Create test folder: PROJECT/app/src/test/java/...

How to use Robolectric?

● @RunWith(RobolectricGradleTestRunner.class)● @Config(constants = BuildConfig.class)● @Config(sdk = Build.VERSION_CODES.KITKAT)● @Config(manifest = “some-path/AndroidManifest.xml”)● @Config(qualifiers = “en-port-hdpi”)

● ./gradlew testDebug● ./gradlew testDebug --tests=”*.TestClassName”

Demo

Drawbacks

● Can not follow the latest Android version○ Robolectric 3.0 supports API 21 (Lollipop) - 2015 August

● Can not cover OEM implementation○ Still need real devices for integration tests

● Still have bugs○ Please report or improve it

PowerMock

What is PowerMock?

● Mock framework extends on EasyMock and Mockito● To enable mocking on:

○ constructors○ static methods○ final classes and methods○ private methods

● Sorry, can not run on Dalvik VM○ Thanks again for Robolectric

How to use PowerMock?

● Build.gradle

dependencies {testCompile "org.powermock:powermock-module-junit4:1.6.1"testCompile "org.powermock:powermock-module-junit4-rule:1.6.1"testCompile "org.powermock:powermock-classloading-xstream:1.6.1"testCompile "org.powermock:powermock-api-mockito:1.6.1"}

How to use PowerMock?

● @PrepareForTest(ClassName.class)● constructor: whenNew()● static method: mockStatic() or stub()● final or private methods: spy()● private member: WhiteBox.setInternalState()

Demo

JaCoCo

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What is Jacoco?

● Java Code Coverage Library● Line and branch coverage● Without injecting code inside your project● Good integration with CI tools like Jenkins● Benefits:

○ Confidence for Team○ Happiness for Boss○ Avoid writing duplicated test code

How to use JaCoCo?

● build.gradle○ apply jacoco plugin○ setup jacoco toolVersion○ add JacocoReport task and depends on testDebug○ setup report format (xml, html, csv)

● Run test with jacoco○ ./gradlew clean jacocoTestReportTask

Demo

Thanks!Any questions?

You can find the sample code on github:https://github.com/chiel99/robolectricDemo

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● Android Engineer● Backend Engineer (Node.js or Python)● Cloud Engineer in Operation● Cloud Engineer in Test● Taiwan Businese Development● Data Scientist● Campaign Testing

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Reference

● http://robolectric.org/● https://github.com/robolectric/robolectric ● http://www.slideshare.net/joemoore1/droidconuk-tdd-android-

with-robolectric● https://github.com/jayway/powermock● http://eclemma.org/jacoco/index.html