Question

The examples I’ve seen for using moq for a repository only show how to mock things being returned. I have a somewhat strange requirement: when a query is executed, if a condition exists, a certain item should be added to the repository. I am wondering how to test this without querying the database. I know how to mock the condition existing, but then how do you setup the mock so that you can test that the certain item is added?

Answer 1

Try to use fake in memory repository instead of moq, for example universal generic repository for all entities:

public interface IInMemoryRepository<T> where T : class
{
    IQueryable<T> GetAll();
    void Create(T item);
    void Update(T item);
    T GetItem(Expression<Func<T, bool>> expression);
    void Delete(T item);
}

public class InMemoryRepository<T> : IInMemoryRepository<T> where T : class
{
    private int _incrementer = 0;
    public Dictionary<int, T> List = new Dictionary<int, T>();

    public IQueryable<T> GetAll()
    {
        return List.Select(x => x.Value).AsQueryable();
    }

    public void Create(T item)
    {
        _incrementer++;
        item.GetType().GetProperties().First(p => p.Name == "Id").SetValue(item, _incrementer, null);
        List.Add(_incrementer, item);
    }

    public void Update(T item)
    {
        var key = (int)item.GetType().GetProperties().First(p => p.Name == "Id").GetValue(item, null);
        List[key] = item;
    }

    public T GetItem(Expression<Func<T, bool>> expression)
    {
        return List.Select(x => x.Value).SingleOrDefault(expression.Compile());
    }

    public void Delete(T item)
    {
        var key = (int)item.GetType().GetProperties().First(p => p.Name == "Id").GetValue(item, null);
        List.Remove(key);
    }
}