public class BaseServices<T> : IBaseService<T> where T : BaseEntity, new()
{
    public List<T> AllItem = new List<T>();

    public bool Delete(int id)
    {
        bool b = false;

        foreach (var a in AllItem)
        {
            if (a.Id == id)
            {
                AllItem.Remove(a);

                b = true;
            }
        }

        return b;
    }

    public T Get(int id)
    {
        T b = null;

        foreach (var a in AllItem)
        {
            if (a.Id == id)
            {
                b = a;
                return b;
            }
        }

        return b;
    }

    public object GetAll()
    {
        object b = null;

        foreach (var a in AllItem)
        {
            b = a;
            return b;
        }

        return b;
    }

    public bool Save(T entity)
    {
        entity = new T();

        AllItem.Add(entity);

        return true;
    }
}

List<AccountModel> Accounts = new List<AccountModel>();

private BaseServices<AccountModel> AccountBS = new BaseServices<AccountModel>();

Random rnd = new Random();

public void Repletion()
{
    for (int index = 0; index < 100; ++index)
    {
        AccountBS.AllItem[index] = new AccountModel();

        AccountBS.AllItem[index].Id = index;

    }

}

[TestMethod]
public void GetTest()
{
    int SomeId = rnd.Next(100);

    AccountModel result = AccountBS.Get(SomeId);

    Assert.IsNotNull(result);
}

private BaseServices<AccountModel> AccountBS = new BaseServices<AccountModel>();
Random rnd = new Random();

[TestInitialize]
public void Repletion()
{
    for (int index = 0; index < 100; ++index)
    {
        AccountBS.AllItem.Add(new AccountModel { Id = index });
    }
}

[TestMethod]
public void GetTest()
{
    int SomeId = rnd.Next(100);

    AccountModel result = AccountBS.Get(SomeId);

    Assert.IsNotNull(result);
}