feat: replace external dependencies with mocks in unit tests

[Gdm0714]

• Remove DynamoDB Local dependency from unit tests
• Replace integration tests with proper unit tests using Mockito
• Add E2E test scenario for real AWS infrastructure validation
• Improve test performance and reliability by eliminating external dependencies
• Add mockito-core dependency to powertools-idempotency-dynamodb module

Summary

Changes

Please provide a summary of what's being changed

Please add the issue number below, if no issue is present the PR might get blocked and not be reviewed

Issue number: #1932

• Removed DynamoDB Local dependency: Eliminated DynamoDBLocal and libsqlite4java-osx-aarch64 dependencies from powertools-idempotency-dynamodb module
• Implemented Mockito-based unit tests: Replaced DynamoDBConfig server setup with @mock annotations and proper unit test patterns
• Updated DynamoDBPersistenceStoreTest: Converted integration-style tests to isolated unit tests that verify business logic without external dependencies
• Enhanced E2E test coverage: Added real AWS infrastructure test scenario in IdempotencyE2ET for comprehensive integration testing
• Added Mockito dependency: Included mockito-core test dependency to support the new mocking approach
• Simplified test setup: Removed complex server startup/shutdown logic and port management code

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[phipag]

Hi @Gdm0714, thank you very much for sending this PR. I will review it next week in more detail.

In the meantime, can you have a look at the 7 new Sonarlint issues? https://sonarcloud.io/project/issues?id=aws-powertools_powertools-lambda-java&pullRequest=1946&issueStatuses=OPEN,CONFIRMED&sinceLeakPeriod=true

• For example, we can remove all public modifiers in unit tests since in Junit5 all classes and methods in unit tests can use the default package private scope.

One question as well:

• Can you explain the additional coverage that you added in the Idempotency E2E test? I don't understand why this is necessary.

[Gdm0714]

Hi! Thank you for the feedback and for taking the time to review this PR.

I'll address the SonarLint issues you mentioned:

• I'll update all test classes and methods to use package-private scope as recommended for JUnit 5.

• You're absolutely right to question this. Looking back at the changes, the additional E2E test scenario I added (test_idempotencyWithRealDynamoDBTable) is actually redundant since the existing E2E tests
  already cover idempotency functionality with real AWS infrastructure.

The main goal of this PR was to replace external dependencies (DynamoDB Local) with mocks in unit tests, not to add more E2E coverage. I can remove this additional E2E test method to keep the scope focused.

Let me push the fixes for

• Remove public modifiers from test classes/methods
• Remove the unnecessary additional E2E test
• Address other SonarLint issues

Thanks again for the review!

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud