erro na classe ClientTest

Compila porem quando servidor sobe espero o resultado mostra que tem um erro, mas não onde.

package br.com.alura.loja;

import javax.ws.rs.client.Client; import javax.ws.rs.client.ClientBuilder; import javax.ws.rs.client.WebTarget;

import org.glassfish.grizzly.http.server.HttpServer; import org.junit.After; import org.junit.Before; import org.junit.Test;

import com.thoughtworks.xstream.XStream;

import br.com.alura.loja.modelo.Carrinho; import junit.framework.Assert;

public class ClienteTest { private HttpServer server;

@Before
public void startaServidor() {
    this.server = Servidor.inicializaServidor();
}

@After
public void mataServidor() {
    server.stop();
}

@Test
public void testaQueBuscarUmCarrinhoTrazOCarrinhoEsperado() {
    Client client = ClientBuilder.newClient();
    WebTarget target = client.target("http://localhost:8080");
    String conteudo = target.path("/carrinhos").request().get(String.class);
    Carrinho carrinho = (Carrinho) new XStream().fromXML(conteudo);
    Assert.assertEquals("Rua Vergueiro 3185, 8 andar", carrinho.getRua());
}

@Test
public void testaQueBuscarUmCarrinhoTrasUmCarrinho() {
    Client client = ClientBuilder.newClient();
    WebTarget target = client.target("http://localhost:8080");
    String conteudo = target.path("/carrinhos/1").request().get(String.class);
    Carrinho fromXML = (Carrinho) new XStream().fromXML(conteudo);
    Assert.assertEquals("Rua Vergueiro 3185, 8 andar",fromXML.getRua());
}

}