[mehrdadn]

> lava flow is a problem in which computer code written under sub-optimal conditions is put into production and added to while still in a developmental state.

I don't know what you're referring to as the "suboptimal code" here. If it's the old pattern using virtual everywhere, then the ship's already sailed... that code is already in production. If you mean the two-file approach I proposed then that makes no sense; if it's worse than the last approach then why would you even use it.

[legulere]

What I meant is that you will end up permanently with multiple solutions for the same problem if you try to change things gradually. This has several drawbacks: Additional complexity having to support both versions, confusion with new developers about which variant to use, a higher likeliness that someone will add a third variant. You have to weigh the benefits of the new alternative against having a more complex code base/doing the grunt work of changing everything at once.

So in this example you have to weigh the benefits of the two file tests against having tests that work uniformly.