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Tag: ci

Cross-service “integration tests” have to go — October 17, 2022

Cross-service “integration tests” have to go

/Valentina Servile/2 Comments

tl;dr They are often broken in pipelines and that might be because they are broken as a concept.

A typical issue in a microservices architecture is ensuring that the integration between services won’t break with the introduction of a new release. In my time as a consultant I have seen different organisations try to tackle this problem with varying degrees of success.

There is one particular approach that I have never seen fully succeed, although it is certainly popular. Organisations often try to have an “integration” test suite in a shared environment that spans several (if not all) services. It usually pokes and prods at functionality owned by multiple teams.

In this article I want to explore why I think these are a bad idea. I will also propose an alternative which is more in line with my understanding of the latest testing good practices.

First, let’s clarify the problem.

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An Isolated Developer Setup with Docker — May 15, 2021

An Isolated Developer Setup with Docker

/Valentina Servile/Leave a comment

In this post I am going to propose a set up to run any kind of application on a developer laptop in complete isolation. It is based on packaging the application into a Docker container, and convince it is still talking to the real world while we’re actually mocking everything around it (spoiler: using more Docker containers).


I have used this in projects of various sizes – from small scale to really chunky applications with lots of intricate dependencies – and has generally proven itself to be worth the initial investment.

In this guide I will assume that the reader is starting from scratch, with an application that is run locally just from their IDE, with no real automation or containerisation. Feel free to skip any of the steps if they are redundant or do not apply to your situation.
I will also assume the reader is familiar with basic concepts of Docker and networking.

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Solving the Docker in Docker dilemma in your CI Pipeline — February 14, 2021

Solving the Docker in Docker dilemma in your CI Pipeline

/Valentina Servile/Leave a comment

There are some tests (integration, end to end, component…) in most modern test suites that rely on some external resources in order to run. Confusing industry terminology aside, their goal is to test the integration between some part of our application and the outside world, like a database or a queue or even some other team’s application.

This is often accomplished by having a Docker container pretend to be the external entity we wish to mock – which is easy enough to set up in a developer’s laptop:

However, things get a bit more tricky once the same test setup has to be run in the team’s CI pipeline.

The reason being, a lot of modern CI/CD tools like Jenkins, GoCD etc. rely on their build agents being Docker containers themselves.

This presents developers who wish to run integration tests in their CI with the task of spawning Docker containers from within other Docker containers, which is not trivial as we are about to see.

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