I have a very large selenium test framework I use to test a web application. It it built around a page-object pattern.
This week I fixed a bug in a low level piece of the framework, but it broke many other pieces that got built on top of this bug. I didn't have a good way to find these spots without running the full test suite of several thousand UI tests.
Since this isn't ideal, what strategy can I use to unit test new functionality and page-object modifications/additions to the framework?
When you change the behaviour of a component in your framework, then just unit-testing that component is not sufficient. You must also re-run the integration- and higher-level tests that involve that component to verify what effect your changes have on the rest of the system.
If you find that the effect of your change is very large, the either you should reconsider the need for the change or bite the bullet and iteratively address the adverse effects.
Quis custodiet ipsos custodes?
Your test framework had bugs in it, which means that your tests were buggy. This is the problem with complex tests and complex testing systems. One way to deal with this is to create unit tests for the complex parts, and then confirm that they behave correctly.
In other words, it's just software, and if it isn't dead simple, it probably needs testing.
You will need to run all tests eventually as you're making a fundamental change. However you don't have to run all tests at once. Rather then fixing the bug, you could deprecate the bug causing functionality, create a new and correct bit of functionality which over time replaces the old functionality.
