Скачать или смотреть Solving Parallel Test Execution Issues with @ EmbeddedKafka in Spring Boot

Learn how to run Kafka integration tests in parallel in your Spring Boot application using @ EmbeddedKafka with a structured solution to avoid resource access exceptions.
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Overcoming Parallel Test Execution Issues with @ EmbeddedKafka in Spring Boot

When working with Spring Boot applications that utilize Apache Kafka, developers often face challenges while running integration tests in parallel. This post tackles a common problem where tests are successfully running in isolation but fail when executed together at the same time, particularly when using the @ EmbeddedKafka annotation.

The Problem at Hand

You may have encountered this scenario: You have several integration tests that implement Kafka functionality, annotated with @ EmbeddedKafka, indicating that each test runs on the same Kafka server (located at localhost:9092). Your test suite executes without issues when run sequentially, but when you try to run them in parallel, you get resource access exceptions.

Understanding the Configuration

In the test suite, your configuration likely looks similar to this:

[[See Video to Reveal this Text or Code Snippet]]

Additionally, your junit-platform.properties file is set up to enable parallel execution:

[[See Video to Reveal this Text or Code Snippet]]

Why Does It Fail?

The issue arises primarily because:

The shared Kafka server is overwhelmed when multiple tests attempt to access it concurrently.

Some tests might be modifying the same topics simultaneously, creating contention and leading to exceptions.

The Solution: Using a Shared Embedded Kafka Broker

Fortunately, there's a structured way to resolve this issue by creating a single EmbeddedKafkaBroker that serves all integration tests. This allows for a dedicated Kafka environment, even when tests are run in parallel.

Step-by-Step Implementation:

Create an Embedded Kafka Broker Bean:
By declaring an EmbeddedKafkaBroker bean, you ensure that all your tests share the same broker. Here's how you can define it:

[[See Video to Reveal this Text or Code Snippet]]

Use Conditional Properties:
Make this bean configurable through separate property files, such that it triggers only for integration tests. This ensures the broker starts on a fixed port, making it available across tests.

Modify Your Tests:
Remove the @ EmbeddedKafka annotation from your tests since the broker will be managed by the Spring context, allowing multiple tests to utilize the same instance seamlessly.

Benefits of This Approach

Efficiency: Reduces resource contention as tests use the same Kafka instance.

Simplicity: Streamlines your test setup, keeping configurations organized without compromising on functionality.

Reliability: Decreases the likelihood of encountering resource access exceptions during parallel execution.

Conclusion

Resolving the complexities associated with parallel execution of Kafka tests in Spring Boot can significantly improve test efficiency and reliability. Leveraging a shared EmbeddedKafkaBroker ensures a smoother testing process without the pitfalls of resource contention or access issues. By adopting this strategy, you can confidently expand your testing suite and make the most of the parallel execution capabilities offered by JUnit 5.

With these changes, your integration tests will run without hindrance, providing a more stress-free development experience. Happy coding!