Don't hard-code class names in __repr__ implementations

[aaronayres35]

fixes #1333

This PR simply updates repr implementations in a few classes to use self.__class__.__name__ rather than hardcoding the class name, and adds simple tests. Namely, it updates the TraitListEvent, TraitDictEvent, and TraitSetEvent classes as well as the AdaptationOffer and WeakIDDict classes.

Checklist

• Tests
  - [ ] Update API reference (docs/source/traits_api_reference)
  - [ ] Update User manual (docs/source/traits_user_manual)
  - [ ] Update type annotation hints in traits-stubs

[rahulporuri]

nit-picky comment : the code might look cleaner if we can use f-strings.

[rahulporuri]

nit : this might look cleaner if we use an f-string.

[mdickinson]

Agreed; and the event -> self switch confused me the first time I looked at this code - just use self throughout.

[aaronayres35]

Agreed; and the event -> self switch confused me the first time I looked at this code - just use self throughout.

I had originally been following what was done here:

traits/traits/observation/_dict_change_event.py

Lines 45 to 52 in 7f8546d

	def __repr__(self):
	return (
	"{event.__class__.__name__}("
	"object={event.object!r}, "
	"removed={event.removed!r}, "
	"added={event.added!r}"
	")".format(event=self)
	)

and with the other _something_change_event reprs. Shall I change these to just use self throughout and f strings as well?

Edit: I went ahead and just did this

[mdickinson]

Ah, I see. Not sure it's worth changing that existing code, given that it's already working. Maybe do that in a separate PR?

Edit: Okay, fine!

[mdickinson]

How about adding a test for a TraitListEvent subclass, to check that it's the subclass name that appears in the repr rather than TraitListEvent. (That's the original motivation for the change, after all.)

[rahulporuri]

LGTM. Not sure if @mdickinson also wants to rereview.

[mdickinson]

LGTM2!