I do that too when I'm testing. I didn't do that in my OP because it didn't seem relevant to the topic. I actually put the counter block outside the group, though.

BEGIN { $static_tests += 3 }
{
   pass 'Group test 1/3';
   pass 'Group test 2/3';
   pass 'Group test 3/3';
}
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I'm not sure if I like that better, but the reasoning behind it was that the block is operating on a variable outside the group, so it should be outside the group. If it's in the group, it might look like it's less relevant to the stuff going on outside, which is not the case.