Тесты Junit проходят по отдельности, но не выполняются вместе ⇐ JAVA

[Anonymous]

Сейчас я работаю над школьным заданием и с трудом справляюсь с тестированием. По какой-то причине модульные тесты работают нормально при индивидуальном запуске, но не при совместном запуске. Я знаю, что это как-то связано с тем, что я делюсь объектом между ними, хотя мне не следует основываться на моих предыдущих поисках, но я не могу хоть убей понять, что нужно изменить, чтобы решить эту проблему. Ниже приведен код как для класса AppointmentService, так и для класса AppointmentServiceTest. Буду очень признателен за любую помощь, так как я застрял на этом уже некоторое время и знаю, что это, вероятно, сразу же увидит кто-то другой.
Класс AppointmentServiceTest

import static org.junit.jupiter.api.Assertions.*;

import java.text.ParseException;

import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import main.Appointment;
import main.AppointmentService;

class AppointmentServiceTest {

private static AppointmentService appointmentService;

@BeforeAll
static void setUp() {
appointmentService = AppointmentService.getService();
}

@Test
void testAddAppointmentSuccess() throws ParseException {
Appointment appointment = new Appointment("123456", "2022-10-01", "Appointment Description String");
assertTrue(appointmentService.addAppointment(appointment));

Appointment cachedAppointment = appointmentService.getAppointment(appointment.getAppointmentId());

assertTrue(cachedAppointment != null);
assertTrue(cachedAppointment.getAppointmentId().equals("123456"));
assertTrue(cachedAppointment.getAppointmentDate().equals("2022-10-01"));
assertTrue(cachedAppointment.getAppointmentDescription().equals("Appointment Description String"));
}

@Test
void testAddMultipleAppointmentsSuccess() throws ParseException {
Appointment appointment1 = new Appointment("123456", "2022-10-01", "Appointment Description String");
Appointment appointment2 = new Appointment("1234567", "2022-10-02", "Appointment Description String2");

assertTrue(appointmentService.addAppointment(appointment1));
Appointment cachedAppointment1 = appointmentService.getAppointment(appointment1.getAppointmentId());

assertTrue(cachedAppointment1 != null);
assertTrue(cachedAppointment1.getAppointmentId().equals("123456"));
assertTrue(cachedAppointment1.getAppointmentDate().equals("2022-10-01"));
assertTrue(cachedAppointment1.getAppointmentDescription().equals("Appointment Description String"));

assertTrue(appointmentService.addAppointment(appointment2));
Appointment cachedAppointment2 = appointmentService.getAppointment(appointment1.getAppointmentId());

assertTrue(cachedAppointment2 != null);
assertTrue(cachedAppointment2.getAppointmentId().equals("1234567"));
assertTrue(cachedAppointment2.getAppointmentDate().equals("2022-10-02"));
assertTrue(cachedAppointment2.getAppointmentDescription().equals("Appointment Description String2"));

}

@Test
void testAddAppoitnmentDuplicateIdFail() throws ParseException {
Appointment appointment1 = new Appointment("123456", "2022-10-01", "Appointment Description String");
Appointment appointment2 = new Appointment("123456", "2022-10-01", "Appointment Description String");

assertTrue(appointmentService.addAppointment(appointment1));
assertFalse(appointmentService.addAppointment(appointment2));
}

@Test
void testGetAppointmentAndUpdateSuccess() throws ParseException {
Appointment appointment = new Appointment("123456", "2022-10-01", "Appointment Description String");
assertTrue(appointmentService.addAppointment(appointment));

Appointment updatedAppointment = appointmentService.getAppointment(appointment.getAppointmentId());
updatedAppointment.setAppointmentDate("2022-10-02");
updatedAppointment.setAppointmentDescription("New Description");

updatedAppointment = appointmentService.getAppointment(updatedAppointment.getAppointmentId());

assertTrue(updatedAppointment.getAppointmentDescription().equals("New Description"));
assertTrue(updatedAppointment.getAppointmentDate().equals("2022-10-02"));
}

@Test
void testGetAppointmentAndDeleteSuccess() throws ParseException {
Appointment appointment = new Appointment("123456", "2022-10-01", "Appointment Description String");

assertTrue(appointmentService.addAppointment(appointment));

appointment = appointmentService.getAppointment(appointment.getAppointmentId());
assertTrue(appointment != null);

assertTrue(appointmentService.deleteAppointment(appointment.getAppointmentId()));
assertTrue(appointmentService.getAppointment(appointment.getAppointmentId()) == null);
}

@Test
void testDeleteInvalidAppointmentFail() {
String invalidAppointmentIdString = "123";

assertFalse(appointmentService.deleteAppointment(invalidAppointmentIdString));
}

И класс AppointmentService

import java.util.HashMap;
import java.util.Map;

public class AppointmentService {

private static AppointmentService reference = new AppointmentService();
private final Map appointmentList;

AppointmentService() {
this.appointmentList = new HashMap();
}

public static AppointmentService getService() {
return reference;
}

public boolean addAppointment(Appointment appointment) {
boolean isSuccess = false;

if(!appointmentList.containsKey(appointment.getAppointmentId())) {
appointmentList.put(appointment.getAppointmentId(), appointment);
isSuccess = true;
}
return isSuccess;
}

public boolean deleteAppointment(String appointmentId) {
return appointmentList.remove(appointmentId) != null;
}

public Appointment getAppointment(String appointmentId) {
return appointmentList.get(appointmentId);
}

}



Подробнее здесь: https://stackoverflow.com/questions/694 ... n-together