@Test
  public void naoDeveDobrarSemLances() {
    Leilao leilao = new Leilao("Macbook Pro 15");
    Usuario steveJobs = new Usuario("Steve Jobs");

    leilao.dobraLance(steveJobs);

    assertEquals(0, leilao.getLances().size());
  }
  @Test
  public void naoDeveAceitarDoisLancesSeguidosDoMesmoUsuarioComUmLance() {
    Leilao leilao = new Leilao("Macbook Pro 15");
    Usuario steveJobs = new Usuario("Steve Jobs");

    leilao.propoe(new Lance(steveJobs, 2000));

    assertEquals(1, leilao.getLances().size());
    assertEquals(2000, leilao.getLances().get(0).getValor(), 0.00001);
  }
  @Test
  public void naoDeveDobrarLancesSequenciaisDoMesmoUsuario() {
    Leilao leilao = new Leilao("Macbook Pro 15");
    Usuario steveJobs = new Usuario("Steve Jobs");
    Usuario billGates = new Usuario("Bill Gates");

    leilao.propoe(new Lance(steveJobs, 2000));
    leilao.propoe(new Lance(billGates, 3000));
    leilao.propoe(new Lance(steveJobs, 4000));

    leilao.dobraLance(steveJobs);

    assertEquals(3, leilao.getLances().size());
  }
  @Test
  public void deveDobrarOUltimoLanceDoUsuario() {
    Leilao leilao = new Leilao("Macbook Pro 15");
    Usuario steveJobs = new Usuario("Steve Jobs");
    Usuario billGates = new Usuario("Bill Gates");

    leilao.propoe(new Lance(steveJobs, 2000));
    leilao.propoe(new Lance(billGates, 3000));

    leilao.dobraLance(steveJobs);

    assertEquals(3, leilao.getLances().size());
    int ultimo = leilao.getLances().size() - 1;
    assertEquals(
        leilao.getLances().get(0).getValor() * 2,
        leilao.getLances().get(ultimo).getValor(),
        0.00001);
  }
  @Test
  public void naoDeveAceitarMaisDoQue5LancesDeUmMesmoUsuario() {
    Leilao leilao = new Leilao("Macbook Pro 15");
    Usuario steveJobs = new Usuario("Steve Jobs");
    Usuario billGates = new Usuario("Bill Gates");

    leilao.propoe(new Lance(steveJobs, 2000));
    leilao.propoe(new Lance(billGates, 3000));
    leilao.propoe(new Lance(steveJobs, 3000));
    leilao.propoe(new Lance(billGates, 3000));
    leilao.propoe(new Lance(steveJobs, 4000));
    leilao.propoe(new Lance(billGates, 3000));
    leilao.propoe(new Lance(steveJobs, 5000));
    leilao.propoe(new Lance(billGates, 3000));
    leilao.propoe(new Lance(steveJobs, 6000));
    leilao.propoe(new Lance(billGates, 999));
    leilao.propoe(new Lance(steveJobs, 7000));

    assertEquals(10, leilao.getLances().size());
    int ultimo = leilao.getLances().size() - 1;
    assertEquals(999, leilao.getLances().get(ultimo).getValor(), 0.00001);
  }