Hi doru in Squeak I started to get some green tests :) Now if you load and try to run testClassSides you get an error because allClasses does not return a model but a collection. classSide ^self isClassSide ifFalse: [self mooseModel allClasses entityNamed: (self mooseName , '_class') asSymbol] ifTrue: [self] can you have a look? Stef