Is there an easy way to setup a link seam with Visual Studio 2010's build system?

I used to have a static library which was imported by both my main program and my tests. However, I needed global variables inside of my static library to be constructed, and there's no way to force Visual Studio to do that.

What I'd like to do then is to have a project which compiles all the common C++ files, a project which compiles and links the unit tests (with the common C++ files), and a project which links the actual application.

How can I do this in Visual Studio 2010?

EDIT: Because clarification has been asked, here's what I mean:

InterfaceIUse.hpp

#include <memory>

struct IInterface
{
    virtual ~IInterface() {}
    virtual void SomethingIDependOn() = 0;
};

std::auto_ptr<IInterf开发者_开发百科ace> FactoryMethod();

CodeUnderTest.cpp

#include "InterfaceIUse.hpp"

void FunctionUnderTest()
{
    //Blah blah blah
}

IExistOnlyInTheMainProgram.cpp

#include "InterfaceIUse.hpp"

std::auto_ptr<IInterface> FactoryMethod()
{
    //I return the real implementation of the interface.
}

IExistOnlyInTheTest.cpp

#include "InterfaceIUse.hpp"

std::auto_ptr<IInterface> FactoryMethod()
{
    //I return the mock implementation of the interface.
}

The idea is to compile the right .cpp implementation of the given factory, which will allow the dependencies of the code to be tested to be dependency injected.

Doing this kind of link seam is easy with makefiles -- but makefiles are undesirable because I'm forced to manually maintain header dependencies in the makefile.

I have done similar setup in VS2008, which I think still applicable for you in VS2010.

To start, I setup my project hierarchy as Build, ProductionCodeBase and TestCodeBase. Common interface/headers are extracted into folder accessible by all projects.

Then in my "Build" project, I manually add object file(s) from ProductionCodeBase into "Release" configuration, and object file(s) from TestCodeBase into "Debug" configuration.

Don't forget to set project dependencies so that object file are valid when linking in "Build".

Do note that you can create project that only compile source code into object files without attempt to link them. Just go to "Tool Build Order" for that particular project and disable corresponding linker.