Apologies if I'm wrong here, but I don't believe any of the major ruby test frameworks use refinements at all. Since they are lexically scoped they end up being too verbose to be useful for this purpose. In other words, you would need to have a series of `using MyRefiningModule` statements in every single test file.
Perhaps you were thinking of rspec's changes in the last few years. They have been moving away from monkeypatching with some changes to their syntax. Previously they defined `Object#should` and handled assertions using syntax like `my_var.should eq(1)`. The new approach, which does not use refinements, is to handle assertions using a wrapper method that works like `expect(my_var).to eq(1)`. No refinements necessary for that though.
Perhaps you were thinking of rspec's changes in the last few years. They have been moving away from monkeypatching with some changes to their syntax. Previously they defined `Object#should` and handled assertions using syntax like `my_var.should eq(1)`. The new approach, which does not use refinements, is to handle assertions using a wrapper method that works like `expect(my_var).to eq(1)`. No refinements necessary for that though.