Linking Visual Studio 2012 C++ Unit Testing project against an exe causes access violations

Question

I'm starting with an existing, monolithic, .exe native Visual Studio 2012 project. I want to add a native Unit Test project alongside, according to http://msdn.microsoft.com/en-us/library/hh419385.aspx#objectRef, which suggests that this is supported:

The code under test is built as an .exe file: Add a separate test project. Link it to the output object file.

I dllexport'ed the methods I needed to test, linked my test project with the exe project's .lib library and things seemed to work for my simple test functions. However, as soon as I tried something more interesting I started getting access violations like this one:

First-chance exception at 0x04fa4aac (TestApplication.exe) in vstest.executionengine.x86.exe: 0xC0000005: Access violation reading location 0x011bf0e0.

So I created a new solution with the simplest .exe and Unity Test project pair I could muster and I was able to reproduce the exceptions with this caller (Unit Test project) and callee (.exe project):

Callee (.exe project) Header.h:

#include <string>
__declspec( dllexport ) std::string __cdecl strTest( std::string j );

Callee (.exe project) Header.cpp:

#include "Header.h"

std::string strTest( std::string j ) {
    std::string output;

    output += j;
    output += "HAHA";

    return output;
}

Caller (Unit Test project) unittest1.cpp:

#include "CppUnitTest.h"
#include "../TestApplication/Header.h"

using namespace Microsoft::VisualStudio::CppUnitTestFramework;

namespace UnitTest {    
    TEST_CLASS(UnitTest1) {
    public:
        TEST_METHOD(TestMethod1) {
            std::string test = strTest( "bla " );
        }
    };
}

The access violation always happens inside the std::string constructor being called by the std::string output; line in strTest().

I made sure that the two projects have identical settings (especially calling convention, optimization/debug settings, bit-ness, and character set). I also disabled and removed the pre-compiled headers for both projects.

I even tried creating a second exe project with the functions above and have my main exe project link against the second exe project. This worked perfectly. When I tried to have my Unit Test project link against that second exe project, in the same way I had my main exe project working, I got the same access violations again.

The only thing that worked was converting my exe project into a dll project (litterally just changing the Configuration Type of my exe project from Application (.exe) to Dynamic Library (.dll)).

So the question is, can I somehow get my exe project unit-testable using Visual Studio 2012's unit testing or should I just start splitting it up into dlls already?

Edit:

I submitted an issue on Microsoft Connect on this and was told that it is indeed a bug: https://connect.microsoft.com/VisualStudio/feedback/details/804696/linking-visual-studio-2012-c-unit-testing-project-against-an-exe-causes-access-violations

I've done some more tests using the same solution I attached on completely fresh installs of Windows 7 Pro x64 SP1 and Windows 8.1 Pro Preview x64 on VMware Workstation 9 virtual machines. Nothing but all Windows updates and the specific Visual Studio was installed for each test. I always reverted to a clean snapshot between tests. I also ran all Visual Studios with all-default settings.

On Windows 7, everything I tried gave me the same access violation. I tried my solution with:

1. Visual Studio Express 2012 for Windows Desktop w/ Update 2
2. Visual Studio Express 2012 for Windows Desktop w/ Update 3
3. Visual Studio 2012 Ultimate w/ Update 3
4. Visual Studio 2013 RC Professional

On Windows 8.1, with Visual Studio Express 2012 for Windows Desktop w/ Update 3 my Unit Tests all ran fine. I'm assuming the other combinations I tried on Windows 7 all work fine on 8.1.

Back on Windows 7, when I switched from x86 to the x64 platform and setting the Default Processor Architecture for the Test Settings to X64 the same test passed. I no longer got access violations.

So this is likely a (Windows 7/x86 platform)-specific problem.

Also, regarding the access violation, it's not always so graceful. I also sometimes get a "vstest.executionengine.x86.exe has stopped working" dialog box with these problem details:

Problem signature:
Problem Event Name:    BEX
Application Name:    vstest.executionengine.x86.exe
Application Version:    12.0.20827.3
Application Timestamp:    521cc637
Fault Module Name:    StackHash_9321
Fault Module Version:    0.0.0.0
Fault Module Timestamp:    00000000
Exception Offset:    00ae9998
Exception Code:    c0000005
Exception Data:    00000008
OS Version:    6.1.7601.2.1.0.256.1
Locale ID:    1033
Additional Information 1:    9321
Additional Information 2:    9321642ea520dd869526c054c7161ae9
Additional Information 3:    bfae
Additional Information 4:    bfaed60192419c1d7d34eac41dbe71a8