As aku says, if you're testing service methods (ie code behaviour) then you can unit test that directly and bypass the WCF infrastructure. Of course, if your code depends on WCF context classes (like OperationContext) then I suggest introducing wrappers much like ASP.NET MVC does for HttpContext.
For testing connectivity, it will depend on the type of endpoints you have configured. In some cases you can just self-host your WCF service inside the unit test (like you would with a WCF Windows Service) and test that.
However, you may need to spin up the ASP.NET Development Web Server or even IIS if you want to test WCF behaviour specific to those hosting environments (ie SSL, authentication methods). This gets tricky and can start making demands on the configuration of everyone's development machine and the build servers but is doable.
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