title: Single vs. Multiple Unit Test Projects per Solution?
body: <p>I have typically had a 1:1 mapping between my product assemblies and my unit test assemblies. I generally try to keep the overall number of assemblies low, and a typical solution may look something like...</p>
  
  <ul>
  <li>Client (Contains Views, Controllers, etc)</li>
  <li>Client.Tests</li>
  <li>Common (Contains Data/Service Contracts, Common Utilities etc)</li>
  <li>Common.Tests</li>
  <li>Server (Contains Domain, Services, etc)</li>
  <li>Server.Tests</li>
  <li>Server.WebHost</li>
  </ul>
  
  <p>Lately at work, people have been mentioning having just a single Unit Test project vs. breaking them down by the assembly that they are testing. I know back in the day, this made life easier if you were running NCover etc as part of your build (no longer matters of course).</p>
  
  <p>What is the general rational behind single vs. multiple UnitTest projects? Other than reducing the number of projects in a solution, is there a concrete reason to go one way or the other? I get the impression this may be one of those "preference" things, but Googling hasn't turned up much.</p>