FileNotFoundException with "new SPSite" Call

This one came back to bite me again, so time to note it down here - when running any test code which accesses a SharePoint web or site using new SPSite(url) in a console application, or in a Visual Studio 2010 test project, it is necessary to adjust the build properties of the project.

The project build configuration (the second tab down in the project properties) need to have the Platform Target explicitly set to x64. If this target is set to x86, or possibly to "Any CPU" then the call to "new SPSite" will fail with "FileNotFoundException", stating that "The web application cannot be found". Next time I'll remember...

Error in Visual Studio 2010 Packaging a SharePoint 2010 Solution

Was getting an error stating that a file "deploys to the same package location" when packaging a SharePoint 2010 solution in VIsual Studio 2010.

Turns out that the SharePointProjectItem.spdata file (in the module subfolder within the Visual Studio project) had somehow gained duplicate entries for a particular file.
To fix this,

1. Unload the project in VS (or close the entire solution)
2. Find the SharePointProjectItem.spdata file in Windows Explorer, and edit in Notepad++ (or your favourite text editor!) to remove the duplicate reference
3. Reload the project in VS, and select that "Package" action - all then worked for me.