pseudocode, because I don't know your project sufficiently well

{ 
   my  $fixture_A = temdir(); # fixture in closure
   
   sub test1 ($fixture_B) {   # no need to repeat A
       # uses fixture A and B
   }

   sub test2 ($fixture_C) {   # no need to repeat A
      # uses fixture A and B
   }

}
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NB: I use "closure" in the original sense, it's the hull with "enclosed vars" not the enclosed sub.

I am sort-of giving up the dependency injection idea, at least for the first pass, as the end result could be achieved by calling the function that returns the fixture.

In your example I wonder what kind of fixture could be such common feature without making the tests accidentally impacting each other. First thought that $fixture_A must be some resource that is not changed during the tests or that we can be sure that they change it in an independent way. (eg. in the case of a tempdir this could mean one of them creates file1.txt the other one creates file2.txt.)

However this sound a bit risky as the tests might accidentally step on each others toes.

However this way it is the decision of the author of the test.

{ 
   my  $fixture_A = temdir(); # fixture in closure
   
   sub test1  {
       my $fixture_B = get_fixture_b();
       # uses fixture A and B
   }

   sub test2  {
       my $fixture_C = get_fixture_c();
      # uses fixture A and B
   }

}
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My take on it
• if a test is called it should have fresh fixtures
• you need to know which variables need to be initialized as fixtures
• you need to know which tests use which fixtures
I think this can be done with a combination of PadWalker to scan the sub, and variable attributes to initialize them as fixture objects.

Unfortunately I'll be several days AFK, so I can't show you a POC.

Anyway I think you are rather inclined to do the PyWay and I've probably missed some edge cases.

(Tho you already mentioned py-decorators, and that's attributes in Perl.)

Feel free to ignore my thoughts and do as you like ...

Hope this helped nonetheless... :)

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}