Problem:
When we add any web test plug in or web request plug in we are getting error “Request failed: Exception occurred: Could not load
file or assembly '<<Solution name>>, Version=1.0.0.0, Culture=neutral,
PublicKeyToken=null' or one of its dependencies. The system cannot find the
file specified.”
Solution : We have to add your .CS file or folder contains file in deployment directory.
Solution items --> Local.test settings --> Deployment --> Enable deployment (check box) and then add file / directory --> Save test settings.