public void AsReadOnlyIListThrowsForNull()
 {
     Assert.ThrowsException <ArgumentNullException>(
         () => CollectionExtensions.AsReadOnly <object>((IList <object>)null));
 }
 public void AsReadOnlyArrayThrowsForNull()
 {
     Assert.ThrowsException <ArgumentNullException>(
         () => CollectionExtensions.AsReadOnly <object>((object[])null));
 }