espresso-onautoscrolledtoview

An Espresso ViewInteraction for finding views that do not exist

Usage

repositories {
  mavenCentral()
}
dependencies {
  androidTestImplementation "com.github.stoyicker.onautoscrolledtoview:library:<version>"
}

Which problem does this solve?

A fairly common issue during Android instrumented tests is failing to find a View. Sometimes, this is because the View just isn't there due to logic or tests being incorrect, for example. But another scenario is that the View is only lazily created and it happens to be beyond the viewport on some devices. This can happen when, for example, you need to locate an element in a RecyclerView. You may use something like RecyclerViewActions.scrollToPosition(), which will work, but can become extremely inconvenient if the content in the RecyclerView changes often, such as for example when using Airbnb's Epoxy, since you'll have to manually maintain the indexes.

To address that, this tool provides the capability of specifying the View that needs to be located not with an index, but with a regular Hamcrest Matcher<View>, exactly the same way as regular Espresso.onView(Matcher<View>) works. In fact, this is how this tool works too: it uses your own matcher to evaluate your matcher against the current view hierarchy: if the evaluation fails, it simulates a finger swipe gesture with the hopes of it resulting in a different view state, and then repeats (or times out); if the evaluations succeeds, it returns Espresso.onView(Matcher<View>) with your matcher.

Note that if for example you have a RecyclerView and want to assert the position of your item in it, you can still include such assertion in the matcher that you provide.

What does it look like?

How do I use it?

There is one method that is your entry point to interacting with this library:

package onautoscrolledtoview;

public final class OnAutoScrolledToView {
  public static void onAutoScrolledToView(Matcher<View>, Matcher<View>, Options)
}

The first parameter is the matcher that describes a condition to use to find your view, the second one is used to find the view to perform scrolling on (must be a direct or indirect parent of the view depicted by the first one), and the third one carries configuration that you may use to customize the scrolling behavior.

You may use Options.builder() to get a builder instance. See Options for documentation and defaults that are used for each field if unset (or when using onAutoScrolledToView(Matcher<View>), the Options-less overload instead).

After the method returns, all you get is the same as when you invoke onView(Matcher<View>) and it returns successfully, so you may continue to use it as such:

onAutoScrolledToView(withId(R.id.your_id)).check(matches(isDisplayed()));

It also works for assertions in the form of matchers, such as doesNotExist():

onAutoScrolledToView(withText("your text")).check(doesNotExist());

See the instrumented tests in demo for more examples.

Compatibility

This library requires API 17. It is implicitly compatible with both LTR and RTL layouts, as well as any type of view.

Versioning

Stable versions of this tool follow espresso-core's versioning. Therefore, every released version is guaranteed to work with the same version of espresso-core. Use with other versions at your own risk.