Should Unit Tests be in their own project in a .Net Solution

Question

Should I start a new project for my unit tests? That would mean that I would get two executables correct? Then I am worried about the namespace organization. Would I be able

Answer 1

Yes. Create a unit test project for each solution project.

There will only be a single executable. The units tests are held in a DLL.

Why not append 'UnitTests' to the relevant namespace.