+1 for inheriting by default.

If ever we don't want to inherit, it's as simple as implementing
shouldInheritSelectors

������ ^false

It's far more simple than implementing isAbstract at class side as we have to do now.

99% of the time we want to inherit, and what we see in order to avoid isAbstract dance is
shouldInheritSelectors
������ ^true

One more word about Pharo version.

In original SUnit we control with these simple two methods:

buildSuiteFromSelectors
������ ^self shouldInheritSelectors
������ ������ ifTrue: [self buildSuiteFromAllSelectors]
������ ������ ifFalse: [self buildSuiteFromLocalSelectors]

shouldInheritSelectors
������ ^self superclass isAbstract
������ ������ or: [self testSelectors isEmpty]

In Pharo this has been refactored:
- buildSuiteFromAllSelectors is not sent, but duplicated in buildSuiteFromSelectors
- buildSuiteFromLocalSelectors is not sent either,
- all happens in allTestSelectors, which has changed of semantic and does not allways answer all tests selectors :(

But the logic seems to remain the same: if the superclass is abstract OR if the set of selectors is empty, then the class will inherit...
If my opinion ever counts, what I see is refactoring for refactoring.
I don't see any new feature, just more unsent selectors, more garbage, and unclear semantic.
I call this runaway refactoring.

There's enough thing to clean in Squeak to avoid "cleaning" what works well no?