Pact JVM VS testcontainers-go

API Contract Testing might be worth exploring. Gives you the ability to run it quickly locally or in CI/CD. A centralized way to validate if your changes broke another service might also be interesting. That series of videos from the same team is gold: https://docs.pact.io

We use Pact for contract testing https://docs.pact.io/

The introduction here is quite good: https://docs.pact.io/

Pact.Net documentation: https://docs.pact.io/ Mountebank documentation: http://www.mbtest.org/ The Microsoft.AspNetCore.TestHost package on GitHub: https://github.com/aspnet/AspNetCore/tree/main/src/Testing/Microsoft.AspNetCore.TestHost

There's also https://docs.pact.io/ but I haven't had time yet to really look into it but probably someone else can tell something about it.

This PoC shows a step by step implementation of contract testing using Pact.

Contract tests assert that inter-application messages conform to a shared understanding documented in a contract. Without contract testing, the only way to ensure that applications will work correctly together is by using expensive and brittle integration tests.

If you are updating your API based on user feedback, you can work with your team or stakeholders to build an API contract describing how your API should function. You can use JSON schemas to document your API’s endpoint response codes and set up the contract. The contract must be accepted by all parties. Then, any changes made to the API must pass the contract test before being approved. Contract testing can be automated and incorporated into your CI/CD pipeline. Contract testing tools include Pact and Spring Cloud Contract.

Pact.

I have contract tests (https://docs.pact.io/) to ensure the integration works.

Let's first look at the original version of the test, in this case, an end-to-end, using testcontainers.

It supports multiple languages (including Go!) and databases (also messaging infrastructure etc.) - All you need is Docker. Testcontainers for Go makes it simple to programmatically create and clean up container-based dependencies for automated integration/smoke tests. You can define test dependencies as code, run tests and delete the containers once done.

Testcontainers Go Documentation

Some of the features: - ✅ Using Vertical Slice Architecture as a high level architecture - ✅ Using Event Driven Architecture on top of RabbitMQ Message Broker with a custom [Event Bus](pkg/messaging/bus/) - ✅ Using Event Sourcing in Audit Based services like [Orders Service](services/orders/) - ✅ Using CQRS Pattern and Mediator Patternon top of Go-MediatR library - ✅ Using Dependency Injection and Inversion of Controlon top of uber-go/fx library - ✅ Using RESTFul api with Echo framework and using swagger with swaggo/swag library - ✅ Using Postgres and EventStoreDB to write databases with fully supports transactions(ACID) - ✅ Using MongoDB and Elastic Search for read databases (NOSQL) - ✅ Using OpenTelemetry for collection Distributed Tracing with using Jaeger and Zipkin - ✅ Using OpenTelemetry for collection Metrics with using Prometheus and Grafana - ✅ Using Unit Test for testing small units with mocking dependent classes and using Mockery for mocking dependencies - ✅ Using End2End Test and Integration Test for testing features with all of their real dependeinces using docker containers (cleanup tests) and testcontainers-go library

For example, you could take a look at this open-source project that helps you spawn docker containers as part of your test setup enabling you to execute queries to a local database.

Using something like TestContainers to spin up a DB for testing has been my best experience. Any mocks leave too much room for error imo

I highly recommend testcontainers for this.

The next block in .gitlab-ci.yml is the services block. Since our tests use testcontainers package and we're pushing a docker container onto Dockerhub, we will need to specify a services block next. Services will enable our pipeline to leverage Docker-in-Docker DinD.