MPT-16437 Reorganise resource billing mixins structure

[albertsola]

Closes MPT-16437

Changes

• Reorganized billing mixins module: Refactored the monolithic mpt_api_client/resources/billing/mixins.py file (426 lines) into a modular package structure with separate files for each mixin type:

  • Created mpt_api_client/resources/billing/mixins/ package with individual mixin modules
  • acceptable_mixin.py: AcceptableMixin and AsyncAcceptableMixin for accept/queue operations
  • regeneratable_mixin.py: RegeneratableMixin and AsyncRegeneratableMixin for regenerate/submit/enquiry/accept operations
  • recalculatable_mixin.py: RecalculatableMixin and AsyncRecalculatableMixin for recalculate/accept/queue operations
  • issuable_mixin.py: IssuableMixin and AsyncIssuableMixin for issue/cancel/error/pending/queue/retry/recalculate operations
  • attachment_mixin.py: AttachmentMixin and AsyncAttachmentMixin combining file CRUD and retrieval operations

• Centralized exports: Created mpt_api_client/resources/billing/mixins/__init__.py to re-export all mixin classes, maintaining the same public API

• Reorganized tests: Refactored test suite structure:

  • Deleted monolithic tests/unit/resources/billing/test_mixins.py (637 lines)
  • Created dedicated test files under tests/unit/resources/billing/mixins/ for each mixin type with comprehensive unit tests covering both synchronous and asynchronous variants

• Maintained backward compatibility: Public API remains unchanged; all previously exported mixins are still available through the updated module structure

[coderabbitai]

📝 Walkthrough

Walkthrough

The monolithic billing mixins module is refactored into a package structure with individual modules for each mixin capability (regeneratable, recalculatable, issuable, acceptable, attachment). A new __init__.py re-exports all mixins to maintain API compatibility. Tests are reorganized from a single comprehensive file into separate per-mixin test modules.

Changes

Cohort / File(s)	Summary
Monolithic Module Removal mpt_api_client/resources/billing/mixins.py	Deleted monolithic mixins file containing 10 mixin classes (RegeneratableMixin, AsyncRegeneratableMixin, RecalculatableMixin, AsyncRecalculatableMixin, IssuableMixin, AsyncIssuableMixin, AcceptableMixin, AsyncAcceptableMixin, AttachmentMixin, AsyncAttachmentMixin).
New Mixins Package Structure mpt_api_client/resources/billing/mixins/__init__.py, mpt_api_client/resources/billing/mixins/acceptable_mixin.py, mpt_api_client/resources/billing/mixins/attachment_mixin.py, mpt_api_client/resources/billing/mixins/issuable_mixin.py, mpt_api_client/resources/billing/mixins/recalculatable_mixin.py, mpt_api_client/resources/billing/mixins/regeneratable_mixin.py	Created new package with individual mixin modules. Package __init__.py centralizes re-exports of all 10 mixin classes. Each module defines synchronous and asynchronous mixin pairs with resource action methods (accept/queue, issue/cancel/error/pending/queue/retry/recalculate, recalculate/accept/queue, regenerate/submit/enquiry/accept, file CRUD operations).
Test Reorganization Removed: tests/unit/resources/billing/test_mixins.py	Deleted monolithic test file containing comprehensive parametrized tests for all mixin classes covering sync/async paths and data presence scenarios.
New Test Modules tests/unit/resources/billing/mixins/test_acceptable_mixin.py, tests/unit/resources/billing/mixins/test_issuable_mixin.py, tests/unit/resources/billing/mixins/test_recalculatable_mixin.py, tests/unit/resources/billing/mixins/test_regeneratable_mixin.py	Created per-mixin test modules with dedicated test services, fixtures, and parametrized test suites validating POST request formation, payload handling, response deserialization, and sync/async behavior for each mixin's action methods.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• MPT-16437 Reorganise resource accounts mixins structure #201: Performs identical refactoring pattern—splits monolithic mixins.py into a package with per-action modules and centralizes re-exports via __init__.py.
• [MPT-16678] Added missing billing statement attachments endpoints #176: Introduces AttachmentMixin composition changes combining CreateFileMixin, UpdateMixin, DeleteMixin, DownloadFileMixin, and GetMixin directly touched by this PR.
• MPT-14900 E2E tests for catalog pricing-policies attachments #133: Related file/attachment mixin refactoring affecting how CreateFileMixin and DownloadFileMixin are composed into attachment operations.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Jira Issue Key In Title	✅ Passed	The PR title contains exactly one Jira issue key (MPT-16437) in the correct MPT-XXXX format at the beginning.
Test Coverage Required	✅ Passed	PR modifies 7 code files reorganizing billing mixins and includes 4 new dedicated test files with 660+ lines of test coverage replacing the old consolidated test file.
Single Commit Required	✅ Passed	The pull request contains exactly one commit (e81d45a) beyond the main branch, satisfying the single commit requirement.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud