Stress Test Concurrency Jpa Entity Random Update

A runnable example in Java to create a cucumber test code files to simulate multiple read and write entity via JPA repository

Sure, here’s an example of a Cucumber test for a JPA repository that simulates multiple read and write operations on an entity:

@RunWith(Cucumber.class)
public class MyEntityRepositorySteps {
    @Autowired
    private MyEntityRepository repository;

    private MyEntity entity;
    private List<MyEntity> entities;

    @Given("an existing entity")
    public void an_existing_entity() {
        entity = new MyEntity();
        entity.setSomeField("value");
        repository.save(entity);
    }

    @When("I retrieve the entity by ID")
    public void i_retrieve_the_entity_by_id() {
        entity = repository.findById(entity.getId()).orElse(null);
    }

    @When("I update the entity")
    public void i_update_the_entity() {
        entity.setSomeField("new value");
        repository.save(entity);
    }

    @When("I retrieve all entities")
    public void i_retrieve_all_entities() {
        entities = repository.findAll();
    }

    @When("I delete the entity")
    public void i_delete_the_entity() {
        repository.delete(entity);
    }

    @Then("the entity is updated")
    public void the_entity_is_updated() {
        MyEntity updatedEntity = repository.findById(entity.getId()).orElse(null);
        assertThat(updatedEntity.getSomeField()).isEqualTo("new value");
    }

    @Then("all entities are retrieved")
    public void all_entities_are_retrieved() {
        assertThat(entities).hasSizeGreaterThan(0);
    }

    @Then("the entity is deleted")
    public void the_entity_is_deleted() {
        MyEntity deletedEntity = repository.findById(entity.getId()).orElse(null);
        assertThat(deletedEntity).isNull();
    }
}

In this example, we have a JPA repository MyEntityRepository that manages MyEntity entities. The test simulates multiple read and write operations on the repository by using Cucumber’s Given-When-Then syntax.

In the Given step, we create and save an entity to the repository. In the When steps, we retrieve, update, retrieve all, and delete the entity using the repository methods. In the Then steps, we assert that the expected changes have been made to the entity and/or the repository.

Note that this is just a simple example to illustrate the basic structure of a Cucumber test for a JPA repository. In a real-world application, you may need to include more complex scenarios, multiple entities, and additional assertions to thoroughly test the repository behavior.

Sample code to implement this with cucumber feature

Here is example of a Cucumber feature file for the JPA repository test scenario I described in my previous answer:

Feature: JPA Repository CRUD operations

  Scenario: Update and delete an existing entity
    Given an existing entity
    When I retrieve the entity by ID
    And I update the entity
    And I delete the entity
    Then the entity is deleted

  Scenario: Retrieve all entities
    Given an existing entity
    When I retrieve all entities
    Then all entities are retrieved

In this feature file, we have two scenarios: “Update and delete an existing entity” and “Retrieve all entities”. Both scenarios use the Given-When-Then syntax to describe the steps of the test.

The first scenario simulates updating and deleting an existing entity using the JPA repository. The second scenario simulates retrieving all entities from the repository.

You can use the Cucumber test code I provided in my previous answer to implement the step definitions for this feature file. Once you have implemented the step definitions, you can run the Cucumber test to execute the scenarios and verify that the JPA repository behaves as expected.

Use case : To simulate 100 thread to read and 2 random threads to update entity

Here’s an example of how you can simulate 100 threads to read and 2 random threads to update an entity using Cucumber and Java threads:

Feature: JPA Repository concurrent access

  Scenario: Concurrent access to an entity
    Given an existing entity
    When I spawn 100 threads to read the entity
    And I spawn 2 random threads to update the entity
    Then the updates are applied to the entity

  Scenario Outline: Concurrent access to multiple entities
    Given <entityCount> existing entities
    When I spawn 100 threads to read the entities
    And I spawn 2 random threads to update the entities
    Then the updates are applied to the entities

    Examples:
      | entityCount |
      | 10          |
      | 50          |
      | 100         |

In the first scenario, we simulate 100 threads to read the entity and 2 random threads to update the entity. In the second scenario, we simulate concurrent access to multiple entities, with the number of entities specified as a parameter in the Examples table.

To implement the step definitions for these scenarios, you can use Java threads to spawn the read and write operations concurrently. Here’s an example of how you can implement the step definitions for the first scenario:

public class JpaConcurrencySteps {
    @Autowired
    private MyEntityRepository repository;

    private MyEntity entity;

    @Given("an existing entity")
    public void an_existing_entity() {
        entity = new MyEntity();
        entity.setSomeField("value");
        repository.save(entity);
    }

    @When("I spawn {int} threads to read the entity")
    public void i_spawn_threads_to_read_the_entity(int threadCount) throws InterruptedException, ExecutionException {
        ExecutorService executor = Executors.newFixedThreadPool(threadCount);
        List<Future<MyEntity>> futures = new ArrayList<>();
        for (int i = 0; i < threadCount; i++) {
            Future<MyEntity> future = executor.submit(() -> repository.findById(entity.getId()).orElse(null));
            futures.add(future);
        }
        List<MyEntity> entities = futures.stream().map(future -> {
            try {
                return future.get();
            } catch (InterruptedException | ExecutionException e) {
                return null;
            }
        }).collect(Collectors.toList());
        executor.shutdown();
        executor.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
        assertThat(entities).hasSize(threadCount);
    }

    @When("I spawn 2 random threads to update the entity")
    public void i_spawn_random_threads_to_update_the_entity() throws InterruptedException {
        Random rand = new Random();
        Thread thread1 = new Thread(() -> {
            entity.setSomeField("value 1");
            repository.save(entity);
        });
        Thread thread2 = new Thread(() -> {
            entity.setSomeField("value 2");
            repository.save(entity);
        });
        if (rand.nextBoolean()) {
            thread1.start();
            thread2.start();
        } else {
            thread2.start();
            thread1.start();
        }
        thread1.join();
        thread2.join();
    }

    @Then("the updates are applied to the entity")
    public void the_updates_are_applied_to_the_entity() {
        MyEntity updatedEntity = repository.findById(entity.getId()).orElse(null);
        assertThat(updatedEntity.getSomeField()).isIn("value 1", "value 2");
    }
}

In this example, we use the ExecutorService and Future classes to spawn multiple threads to read the entity concurrently. We also use the Thread class to spawn two random threads to update the entity concurrently. Finally, we assert that the updates are applied to the entity after