private void showResult(boolean isValidResult) {
        mSuccessView.setVisibility(isValidResult ? View.VISIBLE : View.GONE);
        mErrorView.setVisibility(isValidResult ? View.GONE : View.VISIBLE);
    }
Asks the user for a coffee preparation and shows if it is valid.
<p>Valid inputs are anything ending in "coffee" or strings listed in
{@link MainActivity#COFFEE_PREPARATIONS} The check is always case-insensitive.
</p>
ui/espresso/CustomMatcherSample/app/src/main/java/com/example/android/testing/espresso/CustomMatcherSample/MainActivity.java