So, using NUnit and RhinoMocks:
//Defines basic behavior of all persistable domain objects
public interface IDomainObject {...}
//defines domain objects specific to the Security DB
public interface ISecurityDomainObject : IDomainObject {...}
//Defines a basic transactional data Repository; there are multiple implementors
//which each close TRest to the interface that defines their DB's domain classes
public interface IRepository<TRest> : IDisposable where TRest:IDomainObject
{
IUnitOfWork BeginUnitOfWork();
void CommitUnitOfWork(IUnitOfWork unitOfWork);
void RollBackUnitOfWork(IUnitOfWork unitOfWork);
void Save<T>(T domainObject, IUnitOfWork unitOfWork) where T : class, TRest;
IQueryable<T> QueryFor<T>(IUnitOfWork unitOfWork) where T :class, TRest;
}
public interface ISecurityRepository:IRepository<ISecurityDomainObject> {}
public class SecurityRepository:ISecurityRepository
...
//This line breaks when run in an NUnit test
var securityRepository = MockRepository.GenerateMock<ISecurityRepository>();
...
The error I get is:
System.TypeLoadException : Method 'Save' on type 'ISecurityRepositoryProxyb8e21deb3cb04067a01ac5b63f7045af' from assembly 'DynamicProxyGenAssembly2, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' tried to implicitly implement an interface method with weaker type parameter constraints.
at System.Reflection.Emit.TypeBuilder.TermCreateClass(RuntimeModule module, Int32 tk, ObjectHandleOnStack type)
at System.Reflection.Emit.TypeBuilder.CreateTypeNoLock()
at System.Reflection.Emit.TypeBuilder.CreateType()
at Castle.DynamicProxy.Generators.Emitters.AbstractTypeEmitter.BuildType()
at Castle.DynamicProxy.Generators.InterfaceProxyWithTargetGenerator.GenerateCode(Type proxyTargetType, Type[] interfaces, ProxyGenerationOptions options)
at Castle.DynamicProxy.DefaultProxyBuilder.CreateInterfaceProxyTypeWithoutTarget(Type interfaceToProxy, Type[] additionalInterfacesToProxy, ProxyGenerationOptions options)
at Castle.DynamicProxy.ProxyGenerator.CreateInterfaceProxyTypeWithoutTarget(Type interfaceToProxy, Type[] additionalInterfacesToProxy, ProxyGenerationOptions options)
at Castle.DynamicProxy.ProxyGenerator.CreateInterfaceProxyWithoutTarget(Type interfaceToProxy, Type[] additionalInterfacesToProxy, ProxyGenerationOptions options, IInterceptor[] interceptors)
at Rhino.Mocks.MockRepository.MockInterface(CreateMockState mockStateFactory, Type type, Type[] extras)
at Rhino.Mocks.MockRepository.CreateMockObject(Type type, CreateMockState factory, Type[] extras, Object[] argumentsForConstructor)
at Rhino.Mocks.MockRepository.DynamicMock(Object[] argumentsForConstructor)
at Rhino.Mocks.MockRepository.<>c__DisplayClass7`1.<GenerateMock>b__6(MockRepository r)
at Rhino.Mocks.MockRepository.CreateMockInReplay(Func`2 createMock)
at Rhino.Mocks.MockRepository.GenerateMock(Object[] argumentsForConstructor)
at CSHD.Tests.Unit.Presentation.LoginTests.TestAuthenticationFails() in LoginTests.cs: line 138
When attempting to generate the mock against the concrete class, I get a similar error, this time on the QueryFor() method. If I attempt to redefine the methods that use TRest in the ISecurityRepository interface, I get a "System.BadImageFormatException : An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)" which looks like a step backwards.
I think the core problem is that RhinoMocks is getting confused by the generic parameters being used as generic type restrictions. I have no clue exactly where it's being confused and therefore I don't know how or if I can unconfuse it. I have adequate integration test coverage that I could ignore these failing unit tests if I absolutely have to, but obviously I'd rather fix them if I can. Your thoughts?
It looks like this is a known issue caused by Castle.DynamicProxy that is fixed in the latest trunk of that project, but still broken in the latest Rhino Mocks release:
http://groups.google.com/group/rhinomocks/browse_thread/thread/2c1b53bf66b77b8e/ad09a6cd1e304a93
If you're feeling adventurous you can build your own Rhino Mocks with the latest DynamicProxy and it should be fixed.