[Dúvida] Mockito cannot mock this class

Olá! Estou tentando fazer o teste da classe ValidacaoPetDisponivelTest e também da AdocaoServiceTest. Aparece um erro que o Mockit não consegue fazer o mock da classe. Pesquisei o que poderia ser, até mesmo baixei o código disponibilizado na aula mas não encontrei o erro. Podem ajudar por gentileza? Segue o código das classes.

org.mockito.exceptions.base.MockitoException: 
Mockito cannot mock this class: class br.com.alura.adopet.api.model.Pet.

If you're not sure why you're getting this error, please open an issue on GitHub.


Underlying exception : org.mockito.exceptions.base.MockitoException: Could not modify all classes [class java.lang.Object, class br.com.alura.adopet.api.model.Pet]

    

package br.com.alura.adopet.api.service;

import br.com.alura.adopet.api.dto.SolicitacaoAdocaoDto;
import br.com.alura.adopet.api.model.Abrigo;
import br.com.alura.adopet.api.model.Adocao;
import br.com.alura.adopet.api.model.Pet;
import br.com.alura.adopet.api.model.Tutor;
import br.com.alura.adopet.api.repository.AdocaoRepository;
import br.com.alura.adopet.api.repository.PetRepository;
import br.com.alura.adopet.api.repository.TutorRepository;
import br.com.alura.adopet.api.validacoes.ValidacaoSolicitacaoAdocao;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.ArgumentCaptor;
import org.mockito.Captor;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;

import java.util.List;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.BDDMockito.given;
import static org.mockito.BDDMockito.then;

@ExtendWith(MockitoExtension.class)
class AdocaoServiceTest {

    @InjectMocks
    private AdocaoService service;

    @Mock
    private AdocaoRepository adocaoRepository;

    @Mock
    private PetRepository petRepository;

    @Mock
    private TutorRepository tutorRepository;

    @Mock
    private EmailService emailService;

    @Mock
    private List<ValidacaoSolicitacaoAdocao> validacoes;

    @Mock
    private Pet pet;

    @Mock
    private Tutor tutor;

    @Mock
    private Abrigo abrigo;

    private SolicitacaoAdocaoDto dto;

    @Captor
    private ArgumentCaptor<Adocao> adocaoCaptor;

    @Test
    void deveriaSalvarAdocaoAoSolicitar(){
        //ARRANGE
        this.dto = new SolicitacaoAdocaoDto(10l, 20l, "motivo qualquer");
        given(petRepository.getReferenceById(dto.idPet())).willReturn(pet);
        given(tutorRepository.getReferenceById(dto.idTutor())).willReturn(tutor);
        given(pet.getAbrigo()).willReturn(abrigo);

        //ACT
        service.solicitar(dto);

        //ASSERT
        then(adocaoRepository).should().save(adocaoCaptor.capture());
        Adocao adocaoSalva = adocaoCaptor.getValue();
        assertEquals(pet, adocaoSalva.getPet());
        assertEquals(tutor, adocaoSalva.getTutor());
        assertEquals(dto.motivo(), adocaoSalva.getMotivo());

    }

}

package br.com.alura.adopet.api.validacoes;

import br.com.alura.adopet.api.dto.SolicitacaoAdocaoDto;
import br.com.alura.adopet.api.exception.ValidacaoException;
import br.com.alura.adopet.api.model.Pet;
import br.com.alura.adopet.api.repository.PetRepository;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.BDDMockito;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;

@ExtendWith(MockitoExtension.class)
class ValidacaoPetDisponivelTest {

    @InjectMocks
    private ValidacaoPetDisponivel validacao;
    @Mock
    private PetRepository petRepository;

    @Mock
    private Pet pet;

    @Mock
    private SolicitacaoAdocaoDto dto;

    @Test
    void deveriaPermitirSolicitacaoDeAdocaoPet(){

        //ARRANGE
        BDDMockito.given(petRepository.getReferenceById(dto.idPet())).willReturn(pet);
        BDDMockito.given(pet.getAdotado()).willReturn(false);

        //ASSERT + ACT
        Assertions.assertDoesNotThrow(() -> validacao.validar(dto));
    }

    @Test
    void naoDeveriaPermitirSolicitacaoDeAdocaoPet(){

        //ARRANGE
        BDDMockito.given(petRepository.getReferenceById(dto.idPet())).willReturn(pet);
        BDDMockito.given(pet.getAdotado()).willReturn(true);

        //ASSERT + ACT
        Assertions.assertThrows(ValidacaoException.class,() -> validacao.validar(dto));
    }

}