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Testing REST API integrations using MockServer

Learn how to create a Spring Boot application that integrates with external REST APIs, then test those integrations using Testcontainers and MockServer.

Java Testing with Docker

20 minutes

1

Create the project

2

Write tests

3

Run tests

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Run the tests

$ ./mvnw test

Or with Gradle:

$ ./gradlew test

You should see the MockServer Docker container start in the console output. It acts as the photo service, serving mock responses based on the configured expectations. All tests should pass.

Summary

You built a Spring Boot application that integrates with an external REST API using declarative HTTP clients, then tested that integration using the Testcontainers MockServer module. Testing at the HTTP protocol level instead of mocking Java methods lets you catch serialization issues and simulate realistic failure scenarios.

To learn more about Testcontainers, visit the Testcontainers overview.

Further reading

• Testcontainers MockServer module
• MockServer documentation
• Testcontainers JUnit 5 quickstart