refactor: consolidate codebase structure and add testing infrastructure

[HJLebbink]

Reorganize project structure to improve maintainability and add comprehensive
testing documentation and tooling support.

Structural Changes:

• Convert flat module files to directory modules (builders.rs → builders/mod.rs,
  client.rs → client/mod.rs, response.rs → response/mod.rs)
• Extract core functionality into dedicated modules (error.rs, http.rs, signer.rs)
• Consolidate type definitions under src/s3/types/ with logical grouping:
  • notification/ for S3 event notification types
  • replication/ for bucket replication types
  • serialization/ for select object content types
• Reorganize integration tests under tests/s3/ directory structure

Testing Infrastructure:

• Add .claude/commands for automated coverage analysis and test generation
• Add comprehensive testing documentation (TESTING_STRATEGY.md, TEST_COVERAGE.md)
• Document test architecture explaining unit vs integration test patterns

Developer Experience:

• Expand CLAUDE.md with detailed style guidelines and testing requirements
• Add .claude/QUICKSTART.md for onboarding
• Include MinIO server setup instructions for local testing
• Document expected coverage metrics and realistic goals

Code Organization:

• Split large type files into focused, cohesive modules
• Extract response trait definitions to dedicated file (response_traits.rs)
• Improve utils.rs with additional helper functions
• Add .gitignore entry for coverage artifacts

This consolidation provides a cleaner foundation for continued API development
and establishes clear patterns for testing and documentation.

[Copilot]

Pull Request Overview

This PR performs a comprehensive refactoring to improve code organization and testing infrastructure. The main focus is moving response traits from a_response_traits to response_traits, reorganizing types into logical subdirectories (notification, replication, serialization), and adding extensive test coverage.

Key Changes:

• Consolidates module structure by extracting types into focused subdirectories
• Renames and relocates response trait module from a_response_traits to response_traits
• Adds comprehensive unit tests for utils.rs, signer.rs, and http.rs
• Updates all import paths across 50+ files to reflect new module structure

Reviewed Changes

Copilot reviewed 187 out of 195 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/start-server.sh	Adds MinIO version logging
tests/s3/*.rs	Updates imports from a_response_traits to response_traits
tests/s3/mod.rs	New integration test module structure
tests/s3/list_buckets.rs	Contains debug code for bucket deletion
tests/s3/bucket_notification.rs	Updates SQS ARN format and adds type annotation
tests/s3/listen_bucket_notification.rs	Changes runtime from async-std to tokio
tests/s3/bucket_exists.rs	Corrects region assertion to use DEFAULT_REGION
tests/run-tests-windows.ps1	Sets default region to us-east-1
src/s3/utils.rs	Adds 400+ lines of comprehensive unit tests
src/s3/signer.rs	Adds 350+ lines of signature verification tests
src/s3/http.rs	Adds 600+ lines of URL/endpoint parsing tests
src/s3/types/**/*.rs	New organized type structure with subdirectories
src/s3/response/*.rs	Updates imports to use new response_traits path
src/s3/response_traits.rs	Relocated from a_response_traits with macro improvements
src/s3/mod.rs	Re-exports types module contents
.gitignore	Adds /nul entry

Comments suppressed due to low confidence (5)

tests/s3/list_buckets.rs:51

• Debug/development code is present in the test. The if false block containing bucket deletion logic should be removed before merging. This appears to be leftover debugging code that serves no purpose in the final test.
  tests/s3/bucket_notification.rs:25
• The SQS ARN format has been updated to include the region us-east-1. Ensure this matches the expected MinIO notification configuration format and that the test environment is configured accordingly.
  tests/s3/listen_bucket_notification.rs:16
• The test imports StreamExt from futures_util but the test infrastructure uses tokio. This creates an inconsistent dependency pattern. Consider using tokio_stream::StreamExt for consistency with the tokio runtime used throughout the test.
  tests/s3/listen_bucket_notification.rs:95
• The result of the spawned task is intentionally ignored with let _. Consider checking if the task completed successfully or add a comment explaining why the result can be safely ignored, especially since this is a critical notification listener task.
  tests/s3/bucket_notification.rs:50
• [nitpick] The explicit type annotation : NotificationConfig is redundant since the type can be inferred from the assignment and later comparison. This can be simplified to let config2 = resp.config().unwrap();

[Copilot]

Pull Request Overview

Copilot reviewed 185 out of 193 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (4)

tests/s3/list_buckets.rs:51

• Dead code block with if false should be removed. If this cleanup logic is needed for debugging, consider using a feature flag or environment variable instead of leaving unreachable code in the codebase.
  tests/s3/bucket_notification.rs:50
• [nitpick] The explicit type annotation NotificationConfig is unnecessary here since the type can be inferred from the assignment. This is redundant and can be removed to simplify the code.
  tests/s3/bucket_exists.rs:54
• This TODO comment indicates a potential bug or design issue where the region should be DEFAULT_REGION but is empty. This should either be fixed or converted to a tracked issue rather than leaving a TODO in the test code.
  tests/s3/bucket_create_delete.rs:129
• Duplicate TODO comment indicating the same issue as in bucket_exists.rs. This should be addressed consistently across all tests - either fix the underlying issue or create a tracked issue and remove these TODOs.