I thought once more about this test. I'm reluctant to have this test removed. On the other hand is Adrien right. He states that a lot of test classes are doing calls to methods they created while the test runs. One solution would be to change the test to use perform: to invoke those methods. But that would making tests a bit tedious. So this is not my preferred solution. I tweaked SystemNavigation>>allUnimplementedNonPrimitiveCalls to allUnimplementedNonPrimitiveCallsX "Answer an Array of each message that is sent by an expression in a method but is not implemented by any object in the system." | all meth dict | dict := Dictionary new. all := self systemNavigation allImplementedMessages. self systemNavigation allBehaviorsDo: [:cl | cl selectorsDo: [:sel | meth := cl compiledMethodAt: sel. meth primitive = 0 ifTrue: [ meth messages do: [:m | (all includes: m) ifFalse: [ ((dict at: cl ifAbsentPut: [ Dictionary new ]) at: sel ifAbsentPut: [ OrderedCollection new]) add: m ] ] ] ] ]. ^ dict So the test would be like (SystemNavigation default allUnimplementedNonPrimitiveCallsX associationsSelect: [:a| (a key allSuperclasses includes: TestCase) not ]) isEmpty Would this or something similar be useful or is this just a lot of noise without much of a benefit? Norbert