Boundaries

There are several opinions about the correct boundaries for acceptance tests that can have a big impact in how fast they execute. While it is true that a proof of a working system is achievable only by running tests on the real infrastructure, we find that the cost for the slower tests' execution is too high for the value provided. It isn't uncommon to see developers avoid running the tests when they are too slow, which would provide feedback too late and make them ineffective.

At the end of the day, in terms of acceptance, we are interested in proving the business behavior. And if we design our system well, that kind of abstraction lives in a very specific layer of our system, as we have seen in the previous lesson. Hence, it's a perfectly acceptable trade-off to run our acceptance suite, skipping infrastructural delivery components and hitting the application layer.

If we correctly separate UI concerns and business concerns, for example, by using the...