How to write a pact test for an interface, which is not used by the most recent consumer anymore?

Question

I have a weird situation and I have no idea how to handle it: Let's say I have a consumer C and a provider P.

We did not use Pact, when we implemented these services. So here is the problem: An older version of C needs a specific interface of P, where it provides some information via an url parameter. BUT the newest version of C is not even able to send this kind of request. Since there are still old versions of C out there, we need to ensure this interface is still provided by P and working correctly.

I'm using Pact-JVM and it looks like I have to send this request somehow, else the test will fail. I'm struggling with creating a meaningful test for this scenario. I could create a dummy, that sends the request, but that would not test anything. Does somebody have any idea what to do in this situation?

Answer 1

I would suggest that you check out out the commit of the old version of the consumer, make a new branch from it, add the pact test to that branch, and publish it as normal.

If all else fails (and I would never normally suggest this) you could take your most recently generated pact, hand modify it to match what the old consumer expects, and then manually publish it to the Pact Broker.

Answer 2

If I understand correctly, there are two (or more) versions of C in production with different versions of a contract on P. One option is to publish the old C with a separate name and verify it as normal. Another option is to publish a pact with the same name.

If you do the latter, you'll need to ensure you tag both versions as prod and then on the provider side, you can verify all prod versions the contract using consumer version selectors.