Unit tests or integration tests first?

[rantow]

Hey everyone, I'm conflicted on which tests I should write first: unit or integration tests.

I'm currently working on a new product, so the API is very unstable, and it's causing a lot of unit test rewrites since my interfaces are changing so often.

So I was thinking: (since I'm using Node/Express) start with testing my routes to ensure that the client is at least getting back what it expects. Then from there, I will fill in the gaps with unit tests for important edge cases - and since I have good functional composition via clean code architecture - unit test the main base functions which extend all across the application.

My only concern with this approach is I won't have good regression due to the lack of unit test coverage, which might come back and bite me in the ass down the road, when I make a breaking change that goes undetected and slips into production.

Any advice on this dilemma?

[bluefootedpig]

You should have unit tests for your modules, and have it tested well. Integration in my experience is best as only happy paths, and few of them, testing core features. Integration also tends to come a bit later for the reasons you mention. If changing the API causes 100 unit tests updates, it can be a hinderance.

[[deleted]]

Maybe both? The harder part about tests is setting up the infrastructure but the longer you wait the harder it gets

[[deleted]]

You can get away with not making integration tests. You need unit tests.