The most important thing to remember when designing the data-driven tests is that the data extracted from the data files will be passed to page object methods called from the test methods. In keeping with that model, those methods must be generic enough to take a number of arguments and/or an object as a parameter.

No methods should contain hardcoded data such as server names, usernames, IP addresses, and so on, or anything else that would prevent them from being portable to various test and auto-deployed lab environments. We want to build re-usable class libraries of methods that we can call from the tests and that only need to be updated in one place, the page object class.