How do I get unit tests to run on a x64 platform

Question

I have a C# application that must run in x64 mode. The problem is I try to create unit tests that run methods in the x64 application and the unit test project won't even build. I get the following error when it tries to build.

Error loading C:.....\bin\x64\Debug....UnitTests.dll: Unable to load the test container 'C:.....\bin\x64\Debug....UnitTests.dll' or one of its dependencies. If you build your test project assembly as a 64 bit assembly, it cannot be loaded. When you build your test project assembly, select "Any CPU" for the platform. To run your tests in 64 bit mode on a 64 bit processor, you must change your test settings in the Hosts tab to run your tests in a 32 bit process. Error details: Could not load file or assembly 'file:///C:.....UnitTests\bin\x64\Debug....UnitTests.dll' or one of its dependencies. An attempt was made to load a program with an incorrect format.

I have tried to change the unit test to x64 and also Any CPU and still cannot get it to run. Is there any fix for this?

Answer 1

In VS 2012 and above you can select the default target platform from Test menu under Test Settings|Default Processor Architecture

Answer 2

I'm assuming that you are using Visual Studios testing framework since you mention no other. In VS2010 you can force the testing host to run in x64. Build your assemblies as Any CPU or x64 then set the test host to x64.

http://msdn.microsoft.com/en-us/library/ee782531.aspx