Set Up Espresso

Step 1 Download Support Library

Step 2 Edit build.gradle

dependencies {
  androidTestCompile 'com.android.support.test:runner:0.4'
  // Set this dependency to use JUnit 4 rules
  androidTestCompile 'com.android.support.test:rules:0.4'
  // Set this dependency to build and run Espresso tests
  androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.1'
}
						

And DONE!

Basics of Espresso

Find View, Perform Actions, Check

Find View, Perform Actions, Check

onView(ViewMatcher)
  .perform(ViewAction)
  .check(ViewAssertion)
						

Find View, Perform Actions, Check

onView(withId(android.R.id.button1))
  .perform(ViewAction)
  .check(ViewAssertion)
						

Find View, Perform Actions, Check

onView(withId(android.R.id.button1))
  .perform(click())
  .check(ViewAssertion)
						

Find View, Perform Actions, Check

onView(withId(android.R.id.button1))
  .perform(click())
  .check(matches(withText("BAR")))
						

Combining Matchers

Test case: if the Toolbar title is "FOO"

The title is a TextView with a parent of class Toolbar

onView(allOf(isAssignableFrom(TextView.class),
    withParent(isAssignableFrom(Toolbar.class))))
    .check(matches(withText("FOO")))
						

testCompile 'org.hamcrest:hamcrest-library:1.3'
						

onView(allOf(isAssignableFrom(TextView.class),
    withParent(isAssignableFrom(Toolbar.class))))
    .check(matches(withText("FOO")))
						

GG in this case

<Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="?attr/colorPrimary">
    
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
    
</Toolbar>
						

Custom Matchers

Test case: if the Toolbar title is "FOO"

Veryfy the Toolbar itself, not verify descendant TextView

onView(isAssignableFrom(Toolbar.class))
    .check(ViewAssertion)
						

onView(isAssignableFrom(Toolbar.class))
    .check(Assert this Toolbar has its title "FOO")
						

onView(isAssignableFrom(Toolbar.class))
    .check(matches(withToolbarTitle("FOO")))
						

onView(isAssignableFrom(Toolbar.class))
    .check(matches(withToolbarTitle("FOO")))
						

public static Matcher<View> withToolbarTitle(CharSequence title) {
	return withToolbarTitle(is(title)); // is(T) from Hamcrest
}

public static Matcher<View> withToolbarTitle(final Matcher<CharSequence> textMatcher) {
    checkNotNull(textMatcher);
    return new BoundedMatcher<View, Toolbar>(Toolbar.class) {
        @Override
        public void describeTo(Description description) {
            description.appendText("with title: ");
            textMatcher.describeTo(description);
        }

        @Override
        public boolean matchesSafely(Toolbar toolbar) {
            return textMatcher.matches(toolbar.getTitle());
        }
    };
}
						

Test AdapterView

Using onData

Why not use onView?

onData(ObjectMatcher)
  .DataOptions // reference DataInteraction.java
  .perform(ViewAction)
  .check(ViewAssertion)
						

Click item with String "Americano" in a Spinner

onData(allOf(is(instanceOf(String.class)), is("Americano")))
  .inAdapterView(R.id.spinner)
  .perform(click());
						

Test RecyclerView

RecyclerView is NOT an AdapterView

RecyclerView is a ViewGroup

So, use onView

Click item at position 27

onView(withId(R.id.recycler_view))
   .perform(RecyclerViewActions.actionOnItemAtPosition(27, click()));
						

in build.gradle

androidTestCompile 'com.android.support.test.espresso:espresso-contrib:2.2'
						

More in espresso-contrib

• DrawerLayout
• DatePicker and TimePicker

Idling Resource

When we talk about Espresso's Synchronization, it means...

When doing tests...

• no UI events in the current message queue
• no tasks in the default AsyncTask thread pool

In some cases, we need to define out own Idling Resource

Implement IdlingResource and override three methods

@Override public String getName() {
  return IntentServiceIdlingResource.class.getName();
}
						

@Override public void registerIdleTransitionCallback(
    ResourceCallback resourceCallback) {
    mResourceCallback = resourceCallback;
}
						

@Override public boolean isIdleNow() {
  boolean idle = !isIntentServiceRunning();
  if (idle && resourceCallback != null) {
    mResourceCallback.onTransitionToIdle();
  }
  return idle;
}
						

Register your IdlingResource in test

@Before
public void registerIntentServiceIdlingResource() {
  idlingResource = new IntentServiceIdlingResource(
    InstrumentationRegistry.getTargetContext());
  Espresso.registerIdlingResources(idlingResource);
}

@After
public void unregisterIntentServiceIdlingResource() {
  Espresso.unregisterIdlingResources(idlingResource);
}
						

Run Espresso Test

Step 1 Connect Device

Make sure your device is connected with usb

Step 2 Turn Off Animations

Turn off animations from Settings by opening Developing Options and turning all the following options off:

• Window animation scale
• Transition animation scale
• Animator duration scale

Step 3 Run