Testcontainers

A Year (or more) in Review

Doctoral Researcher @ Institute for Internet Security
- Blockchain Research Group Lead
Consultant @ Styrascosoft GbR
Testcontainers Maintainer and Open Source Enthusiast
Oracle Groundbreaker Ambassador
GitKraken Ambassador
Organizer Software Crafting Meetup Ruhr

Kevin Wittek @kiview

Thanks to Sergei!

(for slides and everything else)

@bsideup

Why do we Test?

Because else we might end up here!

Source: https://watirmelon.blog/2012/01/31/introducing-the-software-testing-ice-cream-cone/

My definiton

For example:

Launch application server
Framework/Library interactions
Interact with external ports (e.g. network, file system, database)

"Tests which interact with external systems/dependencies"

But why a pyramid?

Source: https://labs.spotify.com/2018/01/11/testing-of-microservices/

Testing Honeycomb

Source: https://labs.spotify.com/2018/01/11/testing-of-microservices/, http://blog.thecodewhisperer.com/permalink/integrated-tests-are-a-scam

Integrated Tests

"I use the term integrated test to mean any test whose result (pass or fail) depends on the correctness of the implementation of more than one piece of non-trivial behavior." - J.B. Rainsberger

"A test that will pass or fail based on the correctness of another system." - Spotify

Source: https://labs.spotify.com/2018/01/11/testing-of-microservices/, http://blog.thecodewhisperer.com/permalink/integrated-tests-are-a-scam

Integrated Tests

For example:

We (manually) spin up other services in a local testing environment
We test against other services in a shared testing environment
Changes to your system breaks tests for other systems

Integration Testing Transformation

GenericContainer redis =
    new GenericContainer("redis:3.0.2")
               .withExposedPorts(6379);

redis.start();

// test my stuff

redis.stop();

The Project

testcontainers-java first released in 2015
100% OSS, MIT licensed
65 releases, 149 contributors
Core maintainers
- Richard North
- Sergei Egorov
- Kevin Wittek
Forks in Python, C#, Rust, Go, JS; Scala wrapper

@whichrich

Capabilities

Generic docker container support
- use any Docker image to support tests
Databases (many!) and Stream processing (Kafka, Pulsar)
AWS mocks (Localstack)
Docker Compose
Selenium
Chaos testing

Capabilities (2)

Dynamic port binding and API
WaitStrategies
Docker environment discovery (e.g. docker-machine, DOCKER_HOST, Docker for Mac, Docker for Windows)
Platform independent
- Linux, macOS, Windows 10 (with NPIPE support!)

@ashleymcnamara

Works on Windows too!

JDK13 Compatible!
+ regularly build against openjdk-ea

Users

Spock Extension


@Testcontainers
class TestContainersClassIT extends Specification {


    @Shared
    GenericContainer genericContainer = 
       new GenericContainer("postgres:latest")
            .withExposedPorts(5432)
            .withEnv([
                POSTGRES_USER: "foo"
                POSTGRES_PASSWORD: "secret"
            ])
}

// Set up a redis container
@ClassRule
public static GenericContainer redis =
    new GenericContainer("redis:3.0.2")
               .withExposedPorts(6379);

JUnit4 Rules

Testcontainers-Jupiter (JUnit5)

@Testcontainers
class SomeTest {

    @Container
    private MySQLContainer mySQLContainer = new MySQLContainer();

    @Test
    void someTestMethod() {
        String url = mySQLContainer.getJdbcUrl();
         // create a connection and run test as normal
    }
}

What happened so far...

Jan, 2018 (1.6.x)

Kafka module
"Ryuk" sidecar

@Test
public void testUsage() throws Exception {
  try (KafkaContainer kafka = new KafkaContainer()) {
    kafka.start();
    testKafkaFunctionality(kafka.getBootstrapServers());
  }
}

Apr, 2018 (1.7.x)

Maven BOM
DockerCompose wait Strategies
MockServer module

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.testcontainers</groupId>
            <artifactId>testcontainers-bom</artifactId>
            <version>{{latest_version}}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

new DockerComposeContainer(new File("src/test/resources/compose-test.yml"))
  .withExposedService("redis_1", REDIS_PORT, Wait.forListeningPort())
  .withExposedService("db_1", 3306, Wait.forLogMessage(".*ready for connections.*\\s", 1))
  .withTailChildContainers(true);

Jun, 2018 (1.8.x)

OkHttp transport
Test framework agnostic (Startable interface)
Docker cred. helpers
copyFileToContainer
New modules!
- Pulsar
- Couchbase
- Cassandra

GenericContainer container = new GenericContainer()
	.withCommand("sleep", "3000")
	.withCopyFileToContainer(
	    MountableFile.forClasspathResource(
          "/mappable-resource/"), 
	      containerPath);

Sep, 2018 (1.9.x)

OkHttp by default
Windows npipe support
Registry auth support on Windows
Fix local compose on Windows
Host ports exposing

Testcontainers.exposeHostPorts(localServerPort);
final String rootUrl =
    String.format("http://host.testcontainers.internal:%d/", localServerPort);

Sep, 2018 (1.9.x)

Dynamic port binding in Couchbase module
New modules
- ClickHouse
- PostGIS

Nov, 2018 (1.10.x)

JUnit5 (Jupiter) support
Documentation relaunch
- Code examples from as part of CI
ENV var to turn off Ryuk (TESTCONTAINERS_RYUK_DISABLED=true)
shm + tmpfs settings
Dependabot
New modules
- Neo4j & Elasticsearch

You can see an example test that could 
have been written for it (without using Testcontainers):

<!--codeinclude-->
[Pre-Testcontainers test code]
(../examples/junit5/redis/src/test/java/quickstart/RedisBackedCacheIntTestStep0.java) 
block:RedisBackedCacheIntTestStep0
<!--/codeinclude-->

Dependabot PRs

Dependabot FTW!

Mar, 2019 (1.11.x)

Chaos testing support (toxiproxy)
fsync=off for PostgreSQL module
Drop Netty transport
Reworking shading

Jul, 2019 (1.12.x)

dependsOn API
Improved pull handling
CI for Windows!
- Azure Pipelines with private Windows node
New modules
- DB2, CockroachDB & RabbitMQ

GenericContainer container = new GenericContainer()
        .dependsOn(postgresContainer, kafkaContainer);

Jul, 2019 (1.12.x)

Secure logging defaults for properties and environment variables
Use official Oracle JDBC driver
Support for DockerClient event streaming
Docker Compose --build support
Image pull policies (AgeBasedPullPolicy)

new GenericContainer<>(imageName)
        .withImagePullPolicy(PullPolicy.alwaysPull())

AgeBasedPullPolicy oneHour = new AgeBasedPullPolicy(
  Duration.of(1L, ChronoUnit.HOURS)
);
new GenericContainer<>(imageName)
        .withImagePullPolicy(oneHour)

Mar, 2020 (1.13.x)

Access Docker Compose containers by service name
New modules
- Presto & OrientDB

public DockerComposeContainer environment = 
  new DockerComposeContainer(new File("src/test/resources/compose-test.yml"))
        .withExposedService("redis_1", REDIS_PORT)
        .withExposedService("db_1", 3306);

Optional<ContainerState> result = environment.getContainerByServiceName("db_1");

Future

and Common Pitfalls...

SELF-typing is sometimes a PITA

Pattern defined in "Effective Java"
- Generic type with a recursive type paramter
- MyClass<T extends MyClass<T>>
Doesn't play nice with other JVM languages (Scala, Kotlin)
Confusing for new users and contributors
Not consistent with all modules

Ideas

Using functional Builder-Pattern
- Maybe Lombok @SuperBuilder?
Double Brace Initialization
- People don't like this 😱

Double Brace Initialization 😜

private GenericContainer myContainer = new GenericContainer("myImage:42.23") {{
   withExposedPorts(4711);

   if (System.getenv().get("INSIDE_CI") == null) {
       org.testcontainers.Testcontainers.exposeHostPorts(8080);
   }

}};

Existing Kotlin 😱

val redisContainer = GenericContainer<Nothing>("redis:3-alpine")
                       .apply { 
                          withExposedPorts(6379) 
                       }

TDD workflows

Container startup introduces overhead
Testcontainers should be ephemeral
We still want to avoid test pollution and integrated tests

One more thing...

Welcome reusable containers!

Released in 1.12.3

Moar Future

Testcontainers 2.0
Complete Podman support
- Working with RedHat on making the TC test suite feature parity reference test suite :)
Container-Core
- Test-Framework agnostic
- OO abstraction of Docker containers
Other languages
- More languages and aligning existing forks
- GraalVM (mind=blown)

Fire in OSS land 🔥

Fire in OSS land 🔥🔥

Far Future...

TODO: add Safe Harbor Statement here

Windows Containers on Windows (WCOW)
Orchestrators (Docker Swarm, Kubernetes)
- Maybe one day... (Help from experts welcome!)
Other container engines (e.g. Podman, Firecracker)
Build and test inside containers with full IDE support
- Cloud IDEs
- Visual Studio Code Remote Development

Testcontainers

Kevin Wittek @kiview

Thanks to Sergei!

Why do we Test?

Because else we might end up here!

My definiton

But why a pyramid?

Testing Honeycomb

Integrated Tests

Integrated Tests

Integration Testing Transformation

The Project

Capabilities

Capabilities (2)

Works on Windows too!

JDK13 Compatible! + regularly build against openjdk-ea

Users

Spock Extension

JUnit4 Rules

Testcontainers-Jupiter (JUnit5)

What happened so far...

Jan, 2018 (1.6.x)

Apr, 2018 (1.7.x)

Jun, 2018 (1.8.x)

Sep, 2018 (1.9.x)

Sep, 2018 (1.9.x)

Nov, 2018 (1.10.x)

Dependabot PRs

Dependabot FTW!

Mar, 2019 (1.11.x)

Jul, 2019 (1.12.x)

Jul, 2019 (1.12.x)

Mar, 2020 (1.13.x)

Future

and Common Pitfalls...

SELF-typing is sometimes a PITA

Ideas

Double Brace Initialization 😜

Existing Kotlin 😱

TDD workflows

One more thing...

Welcome reusable containers!

Released in 1.12.3

Moar Future

Fire in OSS land 🔥

Fire in OSS land 🔥🔥

Far Future...

Resources

JDK13 Compatible!
+ regularly build against openjdk-ea