@ilevkivskyi: Are you sure this works correctly? From documentation:

It does “copy” functions and classes (shallow and deeply), by returning the original object unchanged; this is compatible with the way these are treated by the pickle module.

Test:

class Metaclass(type):
  def __copy__(self):
    return 1

class Foo(metaclass=Metaclass):
  pass

>>> copy.copy(Foo)
<class '__main__.Foo'>
>>> Foo.__copy__()
1
>>> copy.copy(Foo) is Foo
True

I do not think your test is really testing this correctly. Nor copying is really working correctly.

Yes, we exactly follow the docs for copy module (classes are treated as immutable, except in Python 3.2 and 2.7, this is why we have __copy__ defined), what is the problem?

Oh, so idea is that copy.copy should return same reference, and __copy__ is here just for compatibility with 3.2 and 2.7 to return something sane? But why is then doing self.__class__(...) and not just returning self? So why is really making a copy? Or you want in 3.2 and 2.7 to be a copy?

Should a test include that t is copy(t) on versions which are not 2.7 and 3.2?

So why is really making a copy?

IIRC, to match the behaviour of 3.2 for other classes. Or maybe it is something to do with picke in 3.2, I am not sure now TBH.

Should a test include that t is copy(t) on versions which are not 2.7 and 3.2?

This is not something super-important, but if you want to make a PR (with a comment quoting copy docs), then we will add it.

Done: #460