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Spring Cloud Azure support for Testcontainers

  • Article
  • Applies to: ✅ Version 5.22.0

This article describes how to integrate Spring Cloud Azure with Testcontainers to write effective integration tests for your applications.

Testcontainers is an open-source framework for providing throwaway, lightweight instances of databases, message brokers, web browsers, or just about anything that can run in a Docker container. It integrates with JUnit, enabling you to write a test class that can start up a container before any of the tests run. Testcontainers is especially useful for writing integration tests that talk to a real backend service.

The spring-cloud-azure-testcontainers library now supports integration testing for the following Azure services:

Service connections

A service connection is a connection to any remote service. Spring Boot's autoconfiguration can consume the details of a service connection and use them to establish a connection to a remote service. When doing so, the connection details take precedence over any connection-related configuration properties.

When you use Testcontainers, you can automatically create connection details for a service running in a container by annotating the container field in the test class.

The @ServiceConnection annotation is processed by xxxContainerConnectionDetailsFactory classes registered with spring.factories. These factories create a ConnectionDetails bean based on a specific Container subclass or the Docker image name.

The following table provides information about the connection details factory classes supported in the spring-cloud-azure-testcontainers JAR:

Connection details factory class Connection details bean
CosmosContainerConnectionDetailsFactory AzureCosmosConnectionDetails
StorageBlobContainerConnectionDetailsFactory AzureStorageBlobConnectionDetails
StorageQueueContainerConnectionDetailsFactory AzureStorageQueueConnectionDetails

Set up dependencies

The following configuration sets up the required dependencies:

<dependency>
  <groupId>org.testcontainers</groupId>
  <artifactId>azure</artifactId>
</dependency>
<dependency>
  <groupId>com.azure.spring</groupId>
  <artifactId>spring-cloud-azure-testcontainers</artifactId>
</dependency>
<dependency>
  <groupId>com.azure.spring</groupId>
  <artifactId>spring-cloud-azure-starter-cosmos</artifactId>
</dependency>

Use Testcontainers

The following code example demonstrates the basic usage of Testcontainers:

@SpringBootTest
@Testcontainers
@ImportAutoConfiguration(classes = { AzureGlobalPropertiesAutoConfiguration.class, AzureCosmosAutoConfiguration.class})
public class CosmosTestcontainersTest {

    @TempDir
    private static File tempFolder;

    @Autowired
    private CosmosClient client;

    @Container
    @ServiceConnection
    static CosmosDBEmulatorContainer cosmos = new CosmosDBEmulatorContainer(
    DockerImageName.parse("mcr.microsoft.com/cosmosdb/linux/azure-cosmos-emulator:latest"));

    @BeforeAll
    static void setup() {
        cosmos.start();
        Path keyStoreFile = new File(tempFolder, "azure-cosmos-emulator.keystore").toPath();
        KeyStore keyStore = cosmos.buildNewKeyStore();
        try {
            keyStore.store(Files.newOutputStream(keyStoreFile.toFile().toPath()), cosmos.getEmulatorKey().toCharArray());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    
        System.setProperty("javax.net.ssl.trustStore", keyStoreFile.toString());
        System.setProperty("javax.net.ssl.trustStorePassword", cosmos.getEmulatorKey());
        System.setProperty("javax.net.ssl.trustStoreType", "PKCS12");
    }

    @Test
    void test() {
        // ...
    }
}

To use CosmosDBEmulatorContainer, we need to prepare a KeyStore for TLS/SSL. For more information, see Cosmos DB Azure Module in the Testcontainers documentation. With @ServiceConnection, this configuration enables Cosmos DB-related beans in the app to communicate with Cosmos DB running inside the Testcontainers-managed Docker container. This action is done by automatically defining a AzureCosmosConnectionDetails bean, which is then used by the Cosmos DB autoconfiguration, overriding any connection-related configuration properties.

Samples

For more information, see the azure-spring-boot-samples repository on GitHub.