test(cleanup): Add repository unit tests

[k8ika0s]

Summary

Adds comprehensive unit tests for the cleanup repository layer, covering all CRUD operations and statistics management.

Changes Made

1. Repository Tests (backend/internal/cleanup/repository_test.go - 428 lines)

• CreateJob Tests: Success and database error cases
• GetJob Tests: Successful retrieval and not found cases
• UpdateJob Tests: Success and not found cases
• ListJobs Tests: With filters and empty results
• DeleteJob Tests: Success and not found cases
• GetJobStats Tests: Success and not found (returns empty stats)
• UpdateJobStats Tests: Success and database error cases

2. Repository Interface Update (backend/internal/cleanup/repository.go)

• Added DBPool interface for database operations
• Modified repository to accept DBPool instead of *pgxpool.Pool
• Enables mocking for unit tests while maintaining production compatibility

3. Dependencies (go.mod, go.sum)

• Added github.com/pashagolub/pgxmock/v4 v4.9.0
• Upgraded github.com/jackc/pgx/v5 to v5.7.4

Testing Performed

✅ All 14 repository unit tests passing

=== RUN   TestRepository_CreateJob
=== RUN   TestRepository_CreateJob/successful_job_creation
=== RUN   TestRepository_CreateJob/database_error
--- PASS: TestRepository_CreateJob (0.00s)
=== RUN   TestRepository_GetJob
=== RUN   TestRepository_GetJob/successful_job_retrieval
=== RUN   TestRepository_GetJob/job_not_found
--- PASS: TestRepository_GetJob (0.00s)
=== RUN   TestRepository_UpdateJob
=== RUN   TestRepository_UpdateJob/successful_job_update
=== RUN   TestRepository_UpdateJob/job_not_found
--- PASS: TestRepository_UpdateJob (0.00s)
=== RUN   TestRepository_ListJobs
=== RUN   TestRepository_ListJobs/list_jobs_with_filters
=== RUN   TestRepository_ListJobs/empty_result
--- PASS: TestRepository_ListJobs (0.00s)
=== RUN   TestRepository_DeleteJob
=== RUN   TestRepository_DeleteJob/successful_job_deletion
=== RUN   TestRepository_DeleteJob/job_not_found
--- PASS: TestRepository_DeleteJob (0.00s)
=== RUN   TestRepository_GetJobStats
=== RUN   TestRepository_GetJobStats/successful_stats_retrieval
=== RUN   TestRepository_GetJobStats/stats_not_found
--- PASS: TestRepository_GetJobStats (0.00s)
=== RUN   TestRepository_UpdateJobStats
=== RUN   TestRepository_UpdateJobStats/successful_stats_update
=== RUN   TestRepository_UpdateJobStats/database_error
--- PASS: TestRepository_UpdateJobStats (0.00s)
PASS
ok  	github.com/k8ika0s/s3-web/backend/internal/cleanup	0.007s

Test Coverage Details

CreateJob

• ✅ Successful job creation with auto-generated ID and timestamp
• ✅ Database error handling

GetJob

• ✅ Successful job retrieval with all fields
• ✅ Not found error (pgx.ErrNoRows)

UpdateJob

• ✅ Successful job status update
• ✅ Not found error (0 rows affected)

ListJobs

• ✅ List with multiple filters (LocationID, Status, Limit, Offset)
• ✅ Empty result handling
• ✅ Proper pagination support

DeleteJob

• ✅ Successful job deletion
• ✅ Not found error (0 rows affected)

GetJobStats

• ✅ Successful stats retrieval
• ✅ Not found returns empty stats (not error)

UpdateJobStats

• ✅ Successful stats upsert (INSERT ... ON CONFLICT)
• ✅ Database error handling

Breaking Changes

None - this is purely additive test coverage.

Dependencies Added

• pgxmock/v4 - PostgreSQL mock for unit testing

Checklist

• Code follows project style guidelines
• Tests added and passing (14 new tests)
• Documentation updated (test comments)
• No breaking changes
• Commit messages follow convention
• Branch is up to date with main

Related Issues

Part of cleanup feature test coverage initiative.
Follows PR #8 (cleanupStore tests) and PR #9 (UI component tests).

Next Steps

• Service layer unit tests
• Activity and workflow tests
• Integration tests with testcontainers
• End-to-end tests