etags

[ygins]

This pull request adds comprehensive integration tests for file-based S3 uploads using the Java AWS SDK, improves S3 multipart upload ETag handling, and enhances the system test infrastructure to support the high-level S3 Transfer Manager. The changes ensure that multipart and single-part uploads are correctly tested and that S3-compatible responses include appropriate ETags, improving compatibility with S3 clients and SDKs.

S3 ETag Handling Improvements:

• Added generation and inclusion of ETag headers in responses for both single-part and multipart upload completion in putOrUploadPartHandler and buildCompleteMultipartUploadXml, ensuring S3 client compatibility. [1] [2] [3]

System Test Enhancements:

• Added a new integration test class Boto3UploadFileIT that tests single-part uploads, multipart uploads, and uploads via the high-level S3TransferManager.uploadFile, verifying round-trip integrity for each method.
• Added the s3-transfer-manager dependency to system-tests/pom.xml to enable use of the high-level transfer manager in tests.

Test Infrastructure Upgrades:

• Enhanced the Docker Compose end-to-end integration test (DockerComposeS3E2EIT) to initialize and clean up S3AsyncClient and S3TransferManager, and to configure multipart thresholds and checksum validation for more realistic S3 client behavior. [1] [2] [3] [4]