static Matcher<View> withHint(final String substring) {
        return withHint(is(substring));
    }
A custom matcher that checks the hint property of an {@link android.widget.EditText}. It
accepts either a {@link String} or a {@link org.hamcrest.Matcher}.
runner/AndroidJunitRunnerSample/app/src/androidTest/java/com/example/android/testing/androidjunitrunnersample/HintMatcher.java