Is it practical to test every edge case when defining a spec for a form entry feature?

Question

I'm starting to learn acceptance testing, and I want to test an ASP.NET MVC app using SpecFlow. Currently I'm writing tests for CRUD scenario
I know it's a completely noobie question, but is it practical to test every edge case in my SpecFlow scenarios? I have a form to fill, it has about 15 fields, do I need to test that, for example, "if field A is valid and field B is not, I should see this validation message on the screen"? Or it should be sufficient to write "if form is correctly filled, I should see "Task added" message"? Should I unit-test model validation separately in this case? Thanks ahead

Answer 1

I tend to look for higher-level behavior in scenarios or acceptance tests than I do with unit tests. Particularly, I'm looking for behavior that's valuable to users or other stakeholders.

In this case, the high-level behavior might be phrased as "the user gets feedback on how to fill in the form". You can then just use one or two examples of how the user gets that feedback, and check that the validation message appears.

You can then put the logic around the specific messages in a unit test.

Acceptance tests, especially if you're using BDD scenarios, aren't really tests. They're examples of how to use the system so that you can use those examples to drive conversation with your business stakeholders, and I would tend to phrase them in the same granularity and terms that the business stakeholder is interested in. BDD isn't a substitute for manual testing, though it can certainly help to reduce the burden.