对通用查询工厂进行单元测试

Question

I have implemented a command/query architecture for a project I am working on, but am having trouble testing my classes that require use of the associated factories. The basis of my architecture can be found here: https://cuttingedge.it/blogs/steven/pivot/entry.php?id=92

In particular, I have something similar to the following

public interface IQueryFactory
{
    TQuery CreateQuery<TQuery, TResult>() 
        where TQuery : IQuery<TResult>;
}

public interface IQuery<TResult>
{
} 

public interface IQueryHandler<in TQuery, out TResult>
    where TQuery : IQuery<TResult>
{
    TResult Execute(TQuery query);
}

public interface IQueryHandlerFactory
{
    IQueryHandler<TQuery, TResult> CreateQueryHandler<TQuery, TResult>()
        where TQuery : IQuery<TResult>;
}

public class GetFooDataQuery : IQuery<IEnumerable<FooData>>
{   
    public int FooId { get; set; }
}

public class GetFooQueryHandler : IQueryHandler<GetFooDataQuery, IEnumerable<FooData>>
{        
    private readonly IFooRepository _fooRepository;

    public GetFooDataQueryHandler(IFooRepository fooRepository)
    {          
        _fooRepository = fooRepository;
    }

    public IEnumerable<FooData> Execute(GetFooDataQuery query)
    {           
        return    _fooRepository.Foo.Where(x => x.fooId > query.FooId).ToList();            
    }
}

My classes that need to query the database have a constructor that includes a query factory and a query handler factory. Everything gets wired up via Ninject.

It works fine, but I am finding it difficult to create Unit tests for any class that includes query factories as I need to include the factories as part of the constructor. Any help would be greatly appreciated.

Answer 1

Create a test repository that implements IFooRepository and pass that to the constructor for GetFooQueryHandler. Since it is your test class, you can set it to known test values for the purposes to testing code that depends on this.

[TestMethod]
public void TestMethod1()
{
    var x = new GetFooQueryHandler(new TestFooRepository
        {
            Foo = new List<FooData>()
        });
    var result = x.Execute(new GetFooDataQuery { FooId = 45 });

}

class TestFooRepository : IFooRepository
{
    public IEnumerable<FooData> Foo { get; set; }
}