Mocking third party service in application-go + BDD-java

I recently started looking into BDD(using Gherkin + Restassured). Need to mock third party servicd, below is my use case.

1. Service-A internally calls Service-B
2. The application is in goLang.
3. The BDD are in Java.

We have a CI pipeline running along, where it generates the rpm and deploys the rpm into VM.
On that VM we are running the BDD(Currently Service-A and Service-B are deployed on the same VM)

Is ther a way i can mock the Service-B, so that i dont have to be dependent on Service-B? If yes what would be the best approach here.

Have tried goLang httptest to mock the service at the unit-test level.
But how the mocking can be done after rpm gets created in pipeline with BDD in place.

Thanks

If your Service A is calling Service B internally, rather than via web or RPC, then you can use dependency injection to inject a "fake" version of your Service B. (Note that this doesn't necessarily involve a dependency injection framework; constructor-based and property-based injection are also valid). If Service B has no interface, extract one and use a thin adapter to call the real service or fake depending on environment.

You won't need to change your scenarios as long as they are only interacting with Service A's user interface or API.

You will need to change the way the build pipeline works, so that it deploys with your fake instead of the real code.

You can even do this at runtime, switching over from the fake to the real thing by having the adapter call the relevant service. The switch or deployment can be triggered by environment variables or by build arguments.

Be careful not to deploy your test service to production though!

If you're using continuous deployment, then the last step in the build pipeline should ideally deploy and test interaction with the real service. If for some reason that's the only way you can work, there are still a couple of things you can do that might help:

• You can stub the data that Service B uses, so that it behaves in a predictable way

• You can use a test instance. Reach out to your service provider and see if they have one for you. I recommend that you should still check that deployment of the real service succeeds, ideally with an automated test of some sort, even if that has to be run in production. It only needs to be a basic smoke test to check that the system is wired up. Note that the easier it is to deploy, the easier it will be to recover from any mistakes; if you can't deploy quickly then you will need to be more thorough in your checking.

If the RPM is created and deployed without any kind of fake or test instance, and you have no way to configure the environment to use such a fake or test instance, then you will not be able to mock it out. The build pipeline has to be a part of deploying a fake. That won't be a problem if you have control over your CI pipeline; otherwise reach out to your build team. They may have experience or be able to point you to someone else who can help you. Great BDD is driven by conversations, after all!