import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import java.util.HashSet;
import org.junit.Assert;
import org.junit.Test;

public class LibraryJsonTest {

    private enum ABC {A}

    private HashSet<ABC> abcs;

    @Test
    public void stupidTest() {
        abcs = new HashSet<>();
        abcs.add(ABC.A);
        Gson gson = new GsonBuilder().create();
        String str = gson.toJson(abcs);
        abcs = gson.fromJson(str, (new HashSet<ABC>()).getClass());
        Assert.assertTrue(abcs.contains(ABC.A));
    }
}