You just have to sign the assembly that wants to use the internals with a key (usually a .snk file) and put this in the AssemblyInfo.cs
[assembly: InternalsVisibleTo(“(name of assembly that wants to see the internals), PublicKey=(public key)”)]
Notice that you have to put the public key and the name of the assembly that wants to see the internals. This is especially interesting when Unit Testing, since you may want to inject dependencies using some internal constructor and internal types.
The extract the public key you may use the sn.exe (Strong Name Utility) that comes with Visual Studio and can be used from the Developer Command Prompt (serach “Visual Studio Tools” using the Windows Search J)
Happy testing, buddies!