It’s absolutely incredible to see, and these two tools are the fundamental ways in which we handle tree-based and stack-based navigation in Composable Architecture applications.

Now what would be really cool is if we could write a test that proves this works as we expect. If you remember, last time we uncovered this bug we first wrote a test to demonstrate the problem before even trying to fix it. Then we fixed the bug, saw it fixed the test, and saw that it fixed the behavior in the simulator too. That was really cool to see because it shows just how much of the behavior of our tools is unit testable, and doesn’t even need to be run in the simulator most of the time.

However, we haven’t even discussed testing when it comes to navigation stacks. But there’s a good reason. The navigation stack tools are a lot more complicated than the presentation tools, and so it was good to just focus on the tools in isolation to start. And on top of that, testing features in a navigation stack is quite a bit more complicated that testing features presented with optional or enum state, and so that’s yet another reason to delay the discussion a bit.

But we are now ready to face it head on. We are going to start by showing what it’s like to test our little toy application as it exists right now, and then see how we can make testing navigation stacks more ergonomic and more powerful.