Espresso Matcher supporting NestedScrollView

BetterScrollToAction.java

package com.capitalone.mobile.wallet.androidtest;

import android.graphics.Rect;
import android.support.test.espresso.PerformException;
import android.support.test.espresso.UiController;
import android.support.test.espresso.ViewAction;
import android.support.test.espresso.matcher.ViewMatchers.Visibility;
import android.support.test.espresso.util.HumanReadables;
import android.support.v4.widget.NestedScrollView;
import android.util.Log;
import android.view.View;
import android.widget.HorizontalScrollView;
import android.widget.ScrollView;

import org.hamcrest.Matcher;

import static android.support.test.espresso.matcher.ViewMatchers.isAssignableFrom;
import static android.support.test.espresso.matcher.ViewMatchers.isDescendantOfA;
import static android.support.test.espresso.matcher.ViewMatchers.isDisplayingAtLeast;
import static android.support.test.espresso.matcher.ViewMatchers.withEffectiveVisibility;
import static org.hamcrest.Matchers.allOf;
import static org.hamcrest.Matchers.anyOf;

/**
 * Enables scrolling to the given view. View must be a descendant of a ScrollView, HorizontalScrollView or
 * NestedScrollView. This is a copy of android.support.test.espresso.action.ScrollToAction because some of our views
 * have nested scroll views which can't be interacted with the default action.
 *
 * Created BetterScrollToAction because normal ScrollToAction doesn't support android.support.v4.widget.NestedScrollView
 *
 * @see android.support.test.espresso.action.ScrollToAction
 */
public class BetterScrollToAction implements ViewAction {
    private static final String TAG = BetterScrollToAction.class.getSimpleName();

    protected int percentVisible = 90;

    @SuppressWarnings("unchecked")
    @Override
    public Matcher<View> getConstraints() {
        return allOf(
                withEffectiveVisibility(Visibility.VISIBLE),
                isDescendantOfA(anyOf(isAssignableFrom(ScrollView.class), isAssignableFrom(HorizontalScrollView.class),
                        isAssignableFrom(NestedScrollView.class))));
    }

    @Override
    public void perform(UiController uiController, View view) {
        if (isDisplayingAtLeast(percentVisible).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(percentVisible).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";
    }
}