title: NUnit fail to build test - No Tests discovered
body: <p>I am working on <code>selenium</code> web driver project. I was able to built tests in <code>Test Explorer</code> and execute. </p>
  
  <p>At once I am getting following errors when rebuilding the solution. </p>
  
  <pre><code>Unit Adapter 3.2.0.0: Test discovery starting
  NUnit VS Adapter 2.0.0.0 discovering tests is started
  NUnit Adapter 3.2.0.0: Test discovery starting
  NUnit VS Adapter 2.0.0.0 discovering tests is started
  Attempt to load assembly with unsupported test framework in  C:\..\CustomerTest.exe
  NUnit VS Adapter 2.0.0.0 discovering test is finished
  Attempt to load assembly with unsupported test framework in  C:\..\LoginTest.exe
  NUnit VS Adapter 2.0.0.0 discovering test is finished
  Exception NUnit.Engine.NUnitEngineException, Exception thrown discovering tests in C:\..\CustomerTest.exe
  Cannot run tests in process - a 32 bit process is required.
  NUnit Adapter 3.2.0.0: Test discovery complete
  Exception NUnit.Engine.NUnitEngineException, Exception thrown discovering tests in C:\..\LoginTest.exe
  Cannot run tests in process - a 32 bit process is required.
  NUnit Adapter 3.2.0.0: Test discovery complete
  ========== Discover test finished: 0 found (0:00:02.5558095) ==========
  </code></pre>
  
  <p>I have changed the default processor architecture in to <code>X64</code>, but issue not resolved. </p>
  
  <p>Please help me to resolve this issue. </p>
  
  <p>Thank  you. </p>