TestContainers + JUnit 5 = elegant integration and e2e tests for microservices

Transcript

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   TestContainers + JUnit 5 = elegant integration and e2e tests

   for microservices Nikolay Kuznetsov @nikolayk812 TESTING UNITED Vienna, 7 November 2019
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   About me • Go developer at Zalando Helsinki • Java

   developer at Infobip, DevExperts • C developer at Samsung, Motorola
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   My testing experience • Unit, integration and end-to-end automated tests

   development • Various organizational structures ◦ Separate QA teams ◦ QA engineers in a dev team ◦ No QA teams/engineers at all
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   Key points • Targeting automated testing • Examples and demos

   in Java: TestContainers-Java, JUnit 5, Spring Boot • Principles are language-agnostic
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   Why integration testing?

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   2 unit tests, 0 integration tests

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   Tests trade-offs

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   None
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   Basic integration test

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    Integration testing evolution • In-memory mocking • Local DBs •

    Vagrant • Docker, Docker Compose • Docker API
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    Docker architecture

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    How to start a container for test? • Shell scripts

    • Maven plugin • Docker Compose • Docker API • MiniKube, Kubernetes
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    Shell scripts

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    Maven plugin github.com/fabric8io/docker-maven-plugin

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    Docker Compose

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    Docker API

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    None
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    TestContainers flavors

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    TestContainers Java • github.com/testcontainers/testcontainers-java • Wraps docker-java library • Docker

    environment autodiscovery • Host port randomization • Containers clean up on JVM shutdown • Readiness waiting strategies
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    As simple as var redis = new GenericContainer("redis:5.0.5") .withExposedPorts(6379); var

    postgres = new PostgreSQLContainer();
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    Docker environment autodiscovery

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    Host port randomization • Prevents port conflicts • Enables parallel

    CI builds • API to get an actual host port
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    Containers cleanup github.com/testcontainers/moby-ryuk

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    Readiness waiting strategies • Host port • HTTP status/body •

    Log message • Docker healthcheck • Combination of above • Custom
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    Demo setup User Service

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    Demo scenario User Service INSERT INTO SELECT FROM

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    Demo github.com/nikolayk812/tu-tc-demo

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    Demo recap • JUnit 5 integration via Extension API ◦

    @TestContainers / @Container • TestContainers Modules ◦ 14 databases ◦ Kafka, MockServer, LocalStack, ToxiProxy, etc
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    JUnit 5 Extensions • Customizable extension points: ◦ Life-cycle phases

    ◦ Parameter resolution ◦ Conditional execution, etc • Extension logic registered with @ExtendsWith
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    github.com/nikolayk812/tu-tc-demo Demo-2: setup User Service

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    Demo-2: scenario User Service POST /users GET /user/<id>

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    Demo-2: Docker network User Service user-alias: 8083 postgres-alias: 5432 localhost:

    32812
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    Demo 2 github.com/nikolayk812/tu-tc-demo

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    Demo-2: recap • Docker network and alias

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    Why end-to-end testing? • Business flows across multiple services •

    Regression, when ◦ + new service ◦ - legacy service
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    Testing/staging deployed cluster Spring Cloud Kubernetes

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    Testing against a deployed cluster • Deploy a new service

    version to the cluster? • Unexpected versions of dependent services • Unexpected database states ◦ Care to clear after the test? • Parallel CI builds?
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    On-demand cluster for E2E tests + Locally and at CI

    machines + Control over dependent services versions - Time to start all containers - Resources: memory and CPU How to do it?
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    Kubernetes for E2E tests?

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    Kubernetes for E2E tests - YAGNI TestContainers + Docker network!

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    E2E test setup User Service Item Service

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    Takeaways • https://testcontainers.org • Balance between flexibility, speed and features

    • Works on Mac, Linux, Windows
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    QUESTIONS ?