Integration test on golang using Docker
According to Wikipedia, the integration test is the phase in software testing, where you combine individual software modules and test them as a group. Integration tests are required to test if the software fulfills the specified functional requirement.
In this article, I am going to show you how to write integration tests. The code example provided here is written in go programming language but the concept is easily transferable to any other languages.
Let us set a premise first, here we are trying to publish and subscribe a message to and from rabbitmq using amqp protocol. We have two functions Publish and Subscribe. Publish takes []byte as an input. Subscribe returns <-chan []byte (channel of []byte).
Let’s look at the code example:
Note: The Code example above is a wrapper around the amqp package. The purpose of the wrapper package is to hide complexity and expose a simpler API.
Now let’s look at the test file for the above code example:
Note: In the above code example, I have used a package called testify to create a test suite and run assertion easily.
We are done with go code, now let’s write Dockerfile and docker-compose.yml to run integration tests using Docker.
Dockerfile is fairly simple. The only thing that I want to point out is CMD instruction that uses a Makefile target called integration-tests. I will get back to the Makefile in a while, for now, let’s look at the docker-compose.yml file.
docker-compose.yml file is also fairly simple. We have two services called tests and rabbitmq, tests service depends upon rabbitmq and both of these services are bound to a network called queue-test.
Let’s look at Makefile now:
The Makefile target tests help us run integration tests and do clean up once we are done. I also want to point out flag --abort-on-container-exit on command docker-compose up this flag helps us terminate rabbitmq once we are done running tests using docker-compose.yml
Now, look at the Makefile target integration-tests, something interesting is going with this command
sh -c “while ! curl -s http://rabbitmq:15672 > /dev/null; do echo waiting for 3s; sleep 3; done”here rabbitmq takes a few seconds to completely start-up; we wait for 3sec and check if rabbitmq is up yet using curl on the URL http://rabbitmq:15672. If it’s up we go to the next command on target (that runs tests) else we again wait for 3sec.
Using tools like Docker and Make we can run integration tests on isolation and clean up after we are done testing our code. Using Docker to run tests also helps us be consistent across the local environment and CI/CD environment making it a lot easier to maintain our test suite. Thank you for reading, look at this Github repo to see the above snippets into action.
