Real Integration Tests for Your Datastore
A presentation at TestingStage in in Kyiv, Ukraine, 02000 by Philipp Krenn
Real Integration Tests for Your Datastore Philipp Krenn @xeraa
Developer
Tests
But the unit tests passed, so… https://twitter.com/Aaronius/status/ 933497253347463168
Integration Tests
Mocks
Mockito, EasyMock, JMock,…
Ich mock mir die Welt widdewidde wie sie mir gefällt
https://www.monkeyuser.com/2018/ happy-flow/
! Unit tests, systems not under your control ! Test real datastore
In-Memory
H2, HSQLDB, Apache Derby,…
Embedded Elasticsearch unsupported in 5.0+ https://www.elastic.co/blog/elasticsearch-the-server
! Often good enough ! Test real datastore, supported systems
Actual Datastore
Local installation Docker container Cloud
Demo
! “Good old approach” ! External dependency, parallelization
Embedded
embedded-elasticsearch https://github.com/allegro/embedded-elasticsearch
Demo
Customization & Mappings .withPlugin(“analysis-stempel”) .withIndex(“cars”, IndexSettings.builder() .withType(“_doc”, getSystemResourceAsStream(“car-mapping.json”))
! IDE support, customization, custom lifecycle ! Custom integration
More embedded datastores https://github.com/flapdoodle-oss/ de.flapdoodle.embed.process
Build Tool
docker-maven-plugin http://dmp.fabric8.io
Run container docker:start docker:stop
Demo
maven-failsafe-plugin https://maven.apache.org/surefire/maven-failsafe-plugin/
! Standard or custom Docker image ! One instance for all tests, no IDE support
Testcontainers Generic
Dependency @ClassRule public static GenericContainer redis = new GenericContainer(“redis:3.0.2”) .withExposedPorts(6379);
Docker Compose integration @ClassRule public static DockerComposeContainer environment = new DockerComposeContainer(new File(“src/test/resources/compose.yml”)) .withExposedService(“elasticsearch_1”, ELASTICSEARCH_PORT, Wait.forHttp(“/”).forStatusCode(200));
Demo
What’s in docker ps -a
Docker for Mac API: socat Linux: Multipurpose relay (SOcket CAT) https://github.com/alpine-docker/socat Only with Docker Compose
Cleanup: Moby Ryuk https://github.com/testcontainers/moby-ryuk
[Ryuk] drops a Death Note, a notebook that allows the user to kill anyone simply by knowing their name and face https://en.wikipedia.org/wiki/Ryuk_(Death_Note)
! IDE support, customization, custom lifecycle ! Hacky configuration
Testcontainers Custom
ElasticsearchContainer https://www.testcontainers.org/modules/elasticsearch/
Demo
More languages Scala, Go, .NET , Python , JavaScript , Rust * * * Early development * *
Selenium 2 / Webdriver VNC screen recording
! IDE support, customization, custom lifecycle ! Custom integration
Docker in Docker Or sidecar
$ docker run -it —rm -v $PWD:$PWD -w $PWD -v /var/run/docker.sock:/var/run/docker.sock maven:3 mvn —projects parent,4_testcontainers-custom test $ docker ps -a
Conclusion
Why Integration Tests
Why not Mocking In-Memory Actual Datastore
How Embedded Build Tool Testcontainers
Code https://github.com/xeraa/integration-test-demo
Questions? Philipp Krenn @xeraa
How are you testing with your database?
- Mocking is not an option since you want to test the actual system.
- In-memory databases, like H2 or HSQLDB, have subtle differences and not all datastores have in-memory cousins.
- Managing and running tests in parallel against the actual datastore is a pain.
So what is the solution? There are some very neat solutions for running embedded datastores based on containers, namely the Docker-Maven-Plugin and Testcontainers. From your tests you can start a lightweight, throwaway instance of your datastore and this talk will walk you through three different approaches and how to make them work for your tests.
Video
Resources
The following resources were mentioned during the presentation or are useful additional information.
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GitHub Demo Code
Demoing multiple approaches of integration tests with Elasticsearch.
