testcontainers / testcontainers-scala

Docker containers for testing in scala

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Testcontainers-scala

Scala wrapper for testcontainers-java that allows using docker containers for functional/integration/unit testing.

TestContainers is a Java 8 library that supports JUnit tests, providing lightweight, throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.

Testcontainers-scala in action: http://dimafeng.com/2016/08/01/testcontainers-selenium/

Why can't I use testcontainers-java in my scala project?

testcontainers-java is awesome and yes, you can use it in scala project but:

  • It's written to be used in JUnit tests
  • DockerComposeContainer<SELF extends DockerComposeContainer<SELF>> - it's not convinient to use its api with this 'recursive generic' from scala

Plus

  • This wrapper provides with scala interfaces, approaches, types
  • This wrapper is integrated with scalatest

Setup

Maven

<!-- Scala 2.11.* -->
<dependency>
    <groupId>com.dimafeng</groupId>
    <artifactId>testcontainers-scala_2.11</artifactId>
    <version>0.16.0</version>
    <scope>test</scope>
</dependency>

<!-- Scala 2.12.* -->
<dependency>
    <groupId>com.dimafeng</groupId>
    <artifactId>testcontainers-scala_2.12</artifactId>
    <version>0.16.0</version>
    <scope>test</scope>
</dependency>

Gradle

testCompile("com.dimafeng:testcontainers-scala_2.11:0.16.0") // Scala 2.11.*
testCompile("com.dimafeng:testcontainers-scala_2.12:0.16.0") // Scala 2.12.*

SBT

libraryDependencies += "com.dimafeng" %% "testcontainers-scala" % "0.16.0" % "test"

Requirements

Quick Start

There are two modes of container launching: ForEachTestContainer and ForAllTestContainer. The first one starts a new container before each test case and then stops and removes it. The second one starts and stops a container only once.

To start using it, you just need to extend one of those traits and override a container val as follows:

import com.dimafeng.testcontainers.{ForAllTestContainer, MySQLContainer}

class MysqlSpec extends FlatSpec with ForAllTestContainer {

  override val container = MySQLContainer()

  it should "do something" in {
    Class.forName(container.driverClassName)
    val connection = DriverManager.getConnection(container.jdbcUrl, container.username, container.password)
    ...
  }
}

This spec has a clean mysql database instance for each of its test cases.

import org.testcontainers.containers.MySQLContainer

class MysqlSpec extends FlatSpec with ForAllTestContainer {

    override val container = MySQLContainer()

    it should "do something" in {
      ...
    }

    it should "do something 2" in {
      ...
    }
}

This spec starts one container and both tests share the container's state.

Container types

Generic Container

The most flexible but less convinient containtainer type is GenericContainer. This container allows to launch any docker image with custom configuration.

class GenericContainerSpec extends FlatSpec with ForAllTestContainer {
  override val container = GenericContainer("nginx:latest",
    exposedPorts = Seq(80),
    waitStrategy = Wait.forHttp("/")
  )

  "GenericContainer" should "start nginx and expose 80 port" in {
    assert(Source.fromInputStream(
      new URL(s"http://${container.containerIpAddress}:${container.mappedPort(80)}/").openConnection().getInputStream
    ).mkString.contains("If you see this page, the nginx web server is successfully installed"))
  }
}

Docker Compose

class ComposeSpec extends FlatSpec with ForAllTestContainer {
  override val container = DockerComposeContainer(new File("src/test/resources/docker-compose.yml"), exposedService = Map("redis_1" -> 6379))

  "DockerComposeContainer" should "retrieve non-0 port for any of services" in {
    assert(container.getServicePort("redis_1", 6379) > 0)
  }
}

Selenium

Before you can use this type of containers, you need to add the following dependencies to your project:

"org.seleniumhq.selenium" % "selenium-java" % "2.53.1"

and

"org.testcontainers" % "selenium" % "1.1.8"

Now you can write a test in this way:

class SeleniumSpec extends FlatSpec with SeleniumTestContainerSuite with WebBrowser {
  override def desiredCapabilities = DesiredCapabilities.chrome()

  "Browser" should "show google" in {
      go to "http://google.com"
  }
}

In this case, you'll obtain a clean instance of browser (firefox/chrome) within container to which a test will connect via remote-driver. See Webdriver Containers for more details.

Mysql

Requires you to add this dependency

class MysqlSpec extends FlatSpec with ForAllTestContainer {

  override val container = MySQLContainer()

  "Mysql container" should "be started" in {
    Class.forName(container.driverClassName)
    val connection = DriverManager.getConnection(container.jdbcUrl, container.username, container.password)
      ...
  }
}

The container can also be customized using the constructor parameters, this snippet will initialize a docker container from a specific docker image, with a specific schema name and specific username/password

class MysqlSpec extends FlatSpec with ForAllTestContainer {

  override val container = MySQLContainer(mysqlImageVersion = "mysql:5.7.18",
                                          databaseName = "testcontainer-scala",
                                          username = "scala",
                                          password = "scala")

  "Mysql container" should "be started" in {
    Class.forName(container.driverClassName)
    val connection = DriverManager.getConnection(container.jdbcUrl, container.username, container.password)
      ...
  }
}

PostgreSQL

Requires you to add this dependency

class PostgresqlSpec extends FlatSpec with ForAllTestContainer  {

  override val container = PostgreSQLContainer()

  "PostgreSQL container" should "be started" in {
    Class.forName(container.driverClassName)
    val connection = DriverManager.getConnection(container.jdbcUrl, container.username, container.password)
      ...
  }
}

Multiple Containers

...
val container = MultipleContainers(MySQLContainer(), GenericContainer(...))

// access to containers
containers.containers._1.containerId // container id of the first container
...

Dependent containers

If configuration of one container depends on runtime state of another one, you can use LazyContainer wrapper as follows:

lazy val container1 = Container1()
lazy val container2 = Container2(container1.port)

val containers = MultipleContainers(LazyContainer(pgContainer), LazyContainer(appContainer))

Fixed Host Port Containers

This container will allow you to map container ports to statically defined ports on the docker host.

...
val container = FixedHostPortGenericGenericContainer("nginx:latest",
    waitStrategy = Wait.forHttp("/"),
    exposedHostPort = 8090,
    exposedContainerPort = 80
  )

Start/Stop hooks

If you want to execute your code after container start or before container stop you can override afterStart() and beforeStop() methods.

class MysqlSpec extends FlatSpec with ForAllTestContainer {

  ...

  override def beforeStop(): Unit = {
    // your code
  }

  override def afterStart(): Unit = {
    // your code
  }
}

Release notes

  • 0.16.0

    • FixedHostPortGenericContainer added
  • 0.15.0

    • Additional configuration parameters for MySQLContainer
    • Improvements to MultipleContainers - container lazy creation for dependent containers
  • 0.14.0

    • TestContainers 1.5.1 -> 1.6.0
  • 0.13.0

    • TestContainers 1.4.3 -> 1.5.1
    • Scala 2.10 support
  • 0.12.0

    • Improvement: afterStart hook now handles exceptions correctly
  • 0.11.0

    • Improvement: containers don't start in ForAllTestContainer if all tests are ignored
  • 0.10.0

    • TestContainers 1.4.2 -> 1.4.3
    • Fix of #8
  • 0.8.0

    • PostgreSQL container
  • 0.7.0

    • TestContainers 1.2.1 -> 1.4.2
  • 0.6.0

    • TestContainers 1.2.0 -> 1.2.1
    • Fix of the afterStart hook
  • 0.5.0

    • TestContainers 1.1.8 -> 1.2.0
  • 0.4.1

    • TestContainers 1.1.7 -> 1.1.8
  • 0.4.0

    • TestContainers 1.1.5 -> 1.1.7
    • Scala cross-building (2.11.* + 2.12.*)
  • 0.3.0

    • TestContainers 1.1.0 -> 1.1.5
    • Start/Stop hooks
  • 0.2.0

    • TestContainers 1.0.5 -> 1.1.0
    • Code refactoring
    • Scala wrappers for major container types

Publishing

$ sbt clean release