Android Testing Support Library: The Nitty Gritty - Zan Markan - Codemotion Milan 2016

Android Testing Support Library
The Nitty Gritty
© Zan Markan 2016 - @zmarkan

Testing 101
• on JVM vs on device
• unit / integration / functional / end to end
• Robolectric, Calabash, Instrumentation, Robotium,
Appium

"Support"
• Android framework vs Support libraries
• Trend to unbundle
• support-v4, appcompat-v7, recyclerview, ...

"The support library is
basically a mountain
of hacks"
— Chris Banes, Google

Android Testing
Support Library

Good Old Times...
• jUnit3 syntax
• Remember
ActivityInstrumentationTestCase2<MainActi
vit>?

More jUnit3 goodness
• overriding setUp() and tearDown()
• testPreﬁxedMethods() &
test_preﬁxedMethods()
• Ignorance Inheritance is bliss

Welcome to the present
• jUnit4 syntax
• No more extending
• @Test, @Before, @After, @AfterClass,...
• ActivityTestRule, InstrumentationRegistry

What else is in there?
• Espresso
• More Espresso (there's a lot to it)
• UIAutomator
• Test Runner
• Test Rules
• ...

What else is in there?

But First...The setup
(note: AS does that on it's own if you create a new project -
these instructions will mostly apply for legacy projects)

Gradle
• Set your test runner to be AndroidJUnitRunner
• Add dependencies
• Voila!

Error:Conﬂict with dependency 'com.android.support:support-annotations'.
Resolved versions for app (23.2.1) and test app (23.1.1) differ.
See http://g.co/androidstudio/app-test-app-conﬂict for details.

Gradle
• Voila!
• Resolve dependencies

Dependency resolutions
• App and Test app depend on different lib versions
• Run ./gradlew :app:dependencies
• ! in the compile and androidTestCompile tasks

Resolve with
• Force dependency versions in the test APK
• exclude dependency (everywhere applicable)
• use Resolution strategy

Force versions in test APK
// Resolve conﬂicts between main and test APK:
androidTestCompile "com.android.support:support-annotations:$rootProject.supportLibraryVersion"
androidTestCompile "com.android.support:support-v4:$rootProject.supportLibraryVersion"
Source: github.com/googlesamples/android-
architecture/blob/todo-mvp/todoapp/app/build.gradle

Gradle
• Resolve dependencies
• Voila!

Espresso - components
• View interactions & assertions
• Hamcrest syntax
• No (unnecessary) waits

Espresso - API
Cheat sheet:
google.github.io/android-testing-support-library/docs/
espresso/cheatsheet

Poking the screen
onView(withId(R.id.button)).perform(click());

Poking the screen
onView(withId(R.id.button)).perform(click());
• allOf, anyOf, ...
• withParent, withText...
• isDisplayed, isDialog...

Espresso - contrib
• RecyclerView
• Drawers
• Pickers
• Accessibility

Espresso++
• Custom matchers
• Custom ViewActions
• Idling resources
• Page objects
• Intent mocking

Custom matchers
• Find a view in the hierarchy
• Good for custom views & components
• Override:
• describeTo
• matchesSafely

Custom matchers
interface MyView{
boolean hasCustomProperty();
}
static BoundedMatcher withCustomPropery() {
return new BoundedMatcher<Object, MyView>(MyView.class){
@Override
public void describeTo(Description description) {
description.appendText("Custom property is enabled");
}
@Override
protected boolean matchesSafely(MyView item) {
return item.hasCustomProperty();
}
};
}

Custom ViewActions
• Same story as matchers, just a bit more extensive
• example allows us to scroll in NestedScrollView
• github.com/zmarkan/Android-Espresso-
ScrollableScroll

Custom ViewActions - API
public class ScrollableUtils {
public static ViewAction scrollableScrollTo() {
return actionWithAssertions(new ScrollableScrollToAction());
}
}

Implementation...
public class ScrollableScrollToAction implements ViewAction{
private static ﬁnal String TAG = com.zmarkan.nestedscroll.action.ScrollableScrollToAction.class.getSimpleName();
@SuppressWarnings("unchecked")
@Override
public Matcher<View> getConstraints() {
return allOf(withEffectiveVisibility(ViewMatchers.Visibility.VISIBLE), isDescendantOfA(anyOf(
isAssignableFromClassOrInterface(ScrollingView.class))));
}
@Override
public void perform(UiController uiController, View view) {
if (isDisplayingAtLeast(90).matches(view)) {
Log.i(TAG, "View is already displayed. Returning.");
return;
}
Rect rect = new Rect();
view.getDrawingRect(rect);
if (!view.requestRectangleOnScreen(rect, true /* immediate */)) {
Log.w(TAG, "Scrolling to view was requested, but none of the parents scrolled.");
}
uiController.loopMainThreadUntilIdle();
if (!isDisplayingAtLeast(90).matches(view)) {
throw new PerformException.Builder()
.withActionDescription(this.getDescription())
.withViewDescription(HumanReadables.describe(view))
.withCause(new RuntimeException(
"Scrolling to view was attempted, but the view is not displayed"))
.build();
}
}
@Override
public String getDescription() {
return "scroll to";
}
}

Implementation...
@Override
public Matcher<View> getConstraints() {
return allOf(withEffectiveVisibility(ViewMatchers.Visibility.VISIBLE), isDescendantOfA(anyOf(
isAssignableFromClassOrInterface(ScrollingView.class))));
}

Implementation...
@Override
public void perform(UiController uiController, View view) {
if (isDisplayingAtLeast(90).matches(view)) {
Log.i(TAG, "View is already displayed. Returning.");
return;
}
Rect rect = new Rect();
view.getDrawingRect(rect);
if (!view.requestRectangleOnScreen(rect, true /* immediate */)) {
Log.w(TAG, "Scrolling to view was requested, but none of the parents scrolled.");
}
uiController.loopMainThreadUntilIdle();
if (!isDisplayingAtLeast(90).matches(view)) {
throw new PerformException.Builder()
.withActionDescription(this.getDescription())
.withViewDescription(HumanReadables.describe(view))
.withCause(new RuntimeException(
"Scrolling to view was attempted, but the view is not displayed"))
.build();
}
}

Don't panic.
• Take something that works
• ...like scrollTo() in regular Espresso for ScrollView
• modify it
• profit

Custom IdlingResource
• A better way to wait
• Use when you have background stuff going on
• Override:
• getName
• isIdleNow
• registerIdleTransitionCallback

public class CustomIdlingResource implements IdlingResource{
private ResourceCallback resourceCallback;
private EventBus bus;
private boolean loadingCompleted = false;
public CustomIdlingResource(EventBus bus){
bus.register(this);
}
public void onEvent(LoadingCompletedEvent event){
loadingCompleted = true;
isIdleNow();
}
}

@Override
public String getName() {
return CustomIdlingResource.class.getName();
}
@Override
public void registerIdleTransitionCallback(
ResourceCallback resourceCallback) {
this.resourceCallback = resourceCallback;
}
@Override
public boolean isIdleNow() {
boolean idle = loadingCompleted;
if (idle && resourceCallback != null) {
resourceCallback.onTransitionToIdle();
bus.unregister(this);
}
return idle;
}
}

Page Object Pattern
• Build your own DSL
• Every screen is a Page
• Page-specific actions and verifications
• (as seen in Calabash, etc...)

Page Class
public class MainViewTestUtils {
public void enterUserName(String text){
/* espresso goes here
*/ }
public void enterPassword(String text){
/* ... */ }
public void pressContinue(){
/* ... */ }
public void assertErrorShown(boolean shown){ /* ... */ }
}

Page Class in test
@Test
public void errorShownWhenPasswordIncorrect(){
MainViewTestUtils view = new MainViewTestUtils();
view.enterUsername(username);
view.enterPassword(incorrectPassword);
view.pressContinue();
view.assertErrorShown(true);
}

To boldly go...

UI Automator
• Interact with any installed app
• Use to create full end-to-end tests
• Can coexist with Espresso in the same app
• Use uiautomatorviewer command to find items in
the hierarchy

UI Automator viewer

UI Automator syntax
UiDevice device = UiDevice.getInstance(InstrumentationRegistry.getInstrumentation();
device.pressHome();
device.ﬁndObject(new UiSelector().descriptionContains("Google search")).clickAndWaitForNewWindow();

Test Runner

Test Runner
• Spins up tests...
• and runs them
• Customise to prepare mocks
• Easier run/debug via command line

Extending the Runner
• Use custom Application class
• Provide mocked dependencies
• Specify this new runner in build.gradle
• Kotlin Test Runner

Extending the Runner
public class CustomRunner extends AndroidJUnitRunner{
@Override
public Application newApplication(ClassLoader cl, String className, Context context)
throws InstantiationException, IllegalAccessException, ClassNotFoundException {
return Instrumentation.newApplication(TestApplication.class, context);
}
}

Running on the Command
line
• Run module/package/class/method
• Run Large/Medium/Small test only
• Shard to run in parallel
• Debug without reinstalling

Simple API
• send commands to runner via ADB (adb shell
[commands])
• am instrument -w -e class
your.full.classname#methodName
your.test.package.name/
your.test.Runner.class
• d.android.com/tools/testing/testing_otheride.html

Test Rules

Test Rules
• Set starting activity / Service
• Replace ActivityInstrumentationTestCase2
• (in most cases)
• Add / Extend to create more components

Test Rules - examples
• MockWebServerRule - sets up MockWebServer
when required
• Source: github.com/artem-zinnatullin/
qualitymatters

Firebase test lab
• Simple setup
• CI support (via gcloud)
• Support for VMs
• firebase.google.com/docs/test-lab
• Robo test for automated testing

Espresso Test
Recorder
• Since AS 2.2 preview 3
• Generates test code after clicking on screen
• (Not necessarily nice code)
• tools.android.com/tech-docs/test-recorder

Above & Beyond?
• Espresso Web for WebViews
• JankTestHelper
• Stuff is being added.

Best of all?

It's all open source!

Pusher
/ˈpʊʃ ər/
noun
1. Platform of APIs for building highly connected apps
2. Hiring in London !

fin
• ! www.spacecowboyrocketcompany.com
• " @zmarkan
• # zan at markan dot me
• $ androidchat.co (zmarkan)
• %& @zmarkan

• google.github.io/android-testing-support-library/
contribute
• Quality Matters - Artem Zinnatulin
• d.android.com/tools/testing-support-library
• github.com/googlesamples/android-testing
• chiuki.github.io/advanced-android-espresso

• Espresso: Brian Legate (Flickr)
• Hyperdrive: Youtube
• Road Runner: BrownZelip (Flickr)
• Back to the future: Youtube
• Titanic / unit tests passing: Twitter

Android Testing Support Library: The Nitty Gritty - Zan Markan - Codemotion Milan 2016

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