Custom Espresso action for AutoCompleteTextView. It replaces the text without showing the annoying popup in your tests.

AutocompleteViewActions.java

public class AutocompleteViewActions {

    public static ViewAction replaceAutocomplete(@Nonnull String stringToBeSet) {
        return actionWithAssertions(new ReplaceAutocompleteTextAction(stringToBeSet));
    }

    /**
     * This is based on {@link ReplaceTextAction}
     * with modifications thanks to "http://www.grokkingandroid.com/how-androids-autocompletetextview-nearly-drove-me-nuts/".
     * <p>
     * It replaces the text without showing the autocomplete popup.
     * Bear in mind it won't work if you use a custom adapter not extending {@link ArrayAdapter}.
     * <p>
     */
    public static class ReplaceAutocompleteTextAction implements ViewAction {
        private final String stringToBeSet;

        public ReplaceAutocompleteTextAction(String value) {
            checkNotNull(value);
            this.stringToBeSet = value;
        }

        @SuppressWarnings("unchecked")
        @Override
        public Matcher<View> getConstraints() {
            return allOf(isDisplayed(), isAssignableFrom(AutoCompleteTextView.class));
        }

        @Override
        public void perform(UiController uiController, View view) {
            AutoCompleteTextView autocomplete = (AutoCompleteTextView) view;

            ArrayAdapter adapter = (ArrayAdapter) autocomplete.getAdapter();
            autocomplete.setAdapter(null);

            ((EditText) view).setText(stringToBeSet);

            autocomplete.setAdapter(adapter);
        }

        @Override
        public String getDescription() {
            return "replace text without showing autocomplete suggestions";
        }
    }
}