Тест №23

import interfaces.Buffer;
import core.Loader;
import interfaces.Entity;
import model.BaseEntity;
import model.Invoice;
import model.StoreClient;
import model.User;
import org.junit.Before;
import org.junit.Test;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.List;
import java.util.Random;

import static org.junit.Assert.*;

public class LoaderTest23 {

    private Buffer buffer;
    private Entity savedEntity;
    private int[] statusesCount;

    @Before
    public void setUp() throws NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
        this.buffer = new Loader();
        Constructor<?>[] constructors = {getConstructor(Invoice.class), getConstructor(StoreClient.class), getConstructor(User.class)};
        Random random = new Random();
        int boundIndex = random.nextInt(25);
        BaseEntity.Status[] statuses = BaseEntity.Status.values();
        this.statusesCount = new int[statuses.length];
        for (int i = 0; i < 25; i++) {
            Constructor<?> constructor = constructors[random.nextInt(constructors.length)];
            Entity entity = (Entity) constructor.newInstance(i, i + 13);
            if (i == boundIndex) {
                this.savedEntity = entity;
            }
            int enumIndex = random.nextInt(statuses.length);
            entity.setStatus(statuses[enumIndex]);
            statusesCount[enumIndex]++;
            this.buffer.add(entity);
        }
    }

    private Constructor<?> getConstructor(Class<?> clazz) throws NoSuchMethodException {
        return clazz.getDeclaredConstructor(int.class, int.class);
    }

     @Test
    public void sizeAfterRemove() {
        int expectedCount = 25 - statusesCount[BaseEntity.Status.SOLD.ordinal()];
        this.buffer.removeSold();
        assertEquals(expectedCount, this.buffer.entitiesCount());
    }
}