Several tests from PharoCorePackageDependenciesTests raise errors because it specify packages not present in pharo 1.2: 'AST-Tests-Core' 'AST-Core' 'AST-Semantic' The error come from: referencesInPackageNamed: pkgNameAsString | pi | pi := PackageOrganizer default packageNamed: pkgNameAsString ifAbsent: [^ self]. .... The package is not found, therefore it returns 'self', later in the code we iterate on that 'self', it raise a DNU Message. Maybe rather that returning self, we should return a more explicit error so that we know directly where does the problem comes from? Anyway, I guess the main problem here is that the packages specified are not present in the image? I opened an issue:http://code.google.com/p/pharo/issues/detail?id=3033