Step 4: Your first Testcontainers integration

From the Testcontainers website, we learn that there is a simple way of running different supported JDBC databases with Docker: https://www.testcontainers.org/usage/database_containers.html

An especially interesting part are JDBC-URL based containers: https://www.testcontainers.org/usage/database_containers.html#jdbc-url

It means that starting to use Testcontainers in our project (once we add a dependency) is as simple as changing a few properties in Spring Boot:

@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT, properties = {
 "spring.datasource.url=jdbc:tc:postgresql:14-alpine://testcontainers/workshop"
})

If we split the magical JDBC url, we see:

• jdbc:tc: - this part says that we should use Testcontainers as JDBC provider

• postgresql:14-alpine:// - we use a PostgreSQL database, and we select the correct PostgreSQL image from the Docker Hub as the image

• testcontainers/workshop - the host name (can be anything) is testcontainers and the database name is workshop. Your choice!

After adding the properties and run the test again. Fixed? Good!

Check the logs.

    13:30:59.352  INFO   --- [    Test worker] o.t.d.DockerClientProviderStrategy       : Found Docker environment with local Npipe socket (npipe:////./pipe/docker_engine)
    13:30:59.369  INFO   --- [    Test worker] org.testcontainers.DockerClientFactory   : Docker host IP address is localhost
    13:30:59.431  INFO   --- [    Test worker] org.testcontainers.DockerClientFactory   : Connected to docker: 
      Server Version: 20.10.11
      API Version: 1.41
      Operating System: Docker Desktop
      Total Memory: 3929 MB
    13:31:03.294  INFO   --- [    Test worker] org.testcontainers.DockerClientFactory   : Ryuk started - will monitor and terminate Testcontainers containers on JVM exit
    13:31:03.295  INFO   --- [    Test worker] org.testcontainers.DockerClientFactory   : Checking the system...
    13:31:03.296  INFO   --- [    Test worker] org.testcontainers.DockerClientFactory   : ✔ Docker server version should be at least 1.6.0
    13:31:03.588  INFO   --- [    Test worker] org.testcontainers.DockerClientFactory   : ✔ Docker environment should have more than 2GB free disk space

As you can see, Testcontainers quickly discovered your environment and connected to Docker. It did some pre-flight checks as well to ensure that you have a valid environment.

Hint 1:

Add the following line to your ~/.testcontainers.properties file to disable these checks and speed up the tests:

checks.disable=true

Hint 2:

Changing the PostgreSQL version is as simple as replacing 14-alpine with, for example, 10-alpine. Try it, but don't forget that it will download the new image from the internet, if it's not already present on your computer.