test: improve test coverage from 76% to 88%

What does this MR do and why?

This MR improves the overall test coverage of the project from approximately 76% to 88%.

The goal is to increase confidence in the codebase by adding missing tests and covering previously untested or partially tested modules.

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Key Improvements

• Added comprehensive tests across multiple modules:

  • Projects/*
  • user_profile/*
  • modes/*
  • batch_mode/*

• Introduced tests for previously untested components

• Improved coverage for:

  • async workflows
  • batch processing
  • UI-related logic

• Added edge case and error-handling scenarios

• Minor refactoring was performed in some source files to improve testability (no business logic changes)

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Coverage Summary

• Before: ~76%
• After: 88%

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Test Files Added / Updated

• tests/test_app.py
• tests/test_bad_issue.py
• tests/test_batch_api_helper.py
• tests/test_batch_service.py
• tests/test_batch_client.py
• tests/test_batch_utils.py
• tests/test_changes.py
• tests/test_fetch_script.py
• tests/test_modes_bad_mrs_batch.py
• tests/test_modes_batch_mode.py
• tests/test_modes_compliance_mode.py
• tests/test_modes_user_profile.py
• tests/test_profile_service.py
• tests/test_profile_ui.py
• tests/test_profile_utils.py
• tests/test_project_ui.py
• tests/test_projects.py
• tests/test_render_user_profile.py
• tests/test_repro_timeout_v3.py

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Notes

• Some tests related to export functionality are conditionally skipped due to optional dependencies (openpyxl/xlsxwriter)
• Coverage improvements focus on meaningful test cases, not just execution coverage

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Remaining Work (Follow-up)

The following modules still require additional coverage:

• gitlab_utils/client.py (~38%)
• modes/team_leaderboard.py (~36%)
• modes/compliance_mode.py (~75%)
• batch_mode/export_service.py (~70%)
• modes/bad_mrs_batch.py (~55%)
• modes/bad_issue.py (~61%)

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How to validate locally

pip install -r requirements.txt
pytest --cov

Expected result:

• ~88% total coverage

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MR acceptance checklist

• Tests added for uncovered modules
• Coverage improved from 76% → 88%
• No breaking changes
• Minor refactoring only for testability
• Known gaps documented