Sometimes, it is needed to expose some attribute of a class that is internal or sometimes it is needed to expose an internal class. Basically, it is needed to carry out Unit testing as generally we have unit test code residing in another project.
We can expose an internal class or any internal attribute of a class by using the following attribute:
[assembly: InternalsVisibleTo("AssemblyNameOfTheProjectToWhichTheInternalOfThisClassWillBeVisible, PublicKey= 0000public key of assembly(optional)000")]
public class MyInternalWillBeExposedToSpecificOutsideProject
internal void SomeMethod()