Python: Achieve 85%+ unit test coverage for azurefunctions package

[Copilot]

Motivation and Context

The azurefunctions GA package required 85% unit test coverage. Initial state: 80% coverage with significant gaps in error handling, edge cases, and utility methods.

Description

Increased coverage from 80% to 86% through surgical test additions targeting uncovered code paths.

Coverage by module:

• _errors.py: 50% → 100% (4 tests added)
• _entities.py: 86% → 100% (5 tests added)
• _orchestration.py: 93% → 100% (2 tests added)
• _app.py: 77% → 81% (10 tests added)

Test additions:

• test_errors.py: New file for exception initialization and custom status codes
• test_entities.py: Input validation, event loop handling, async edge cases
• test_orchestration.py: Exception handling during response conversion, UUID generation
• test_app.py: Parameter validation, utility methods, boolean coercion, JSON parsing

Code quality improvements:

• Fixed SIM117 linting violations by combining nested with statements in test files
• Removed unused variables and unreachable code based on PR review feedback
• Removed brittle line number references from test docstrings for better maintainability
• Improved test clarity and documentation to accurately describe tested behavior

All tests follow existing patterns. No breaking changes. Test suite: 80 → 101 tests.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Python: azurefunctions package unit test coverage tracking</issue_title>
<issue_description>### Description

Track and ensure the azurefunctions GA package achieves 85% unit test coverage as part of the overall requirement. Report current status, gaps, and actions needed to meet the threshold.

Package Versions

agent-framework-azurefunctions</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Python: azurefunctions package unit test coverage tracking #3355

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[larohra]

@copilot can you fix the failing checks

[Copilot]

@copilot can you fix the failing checks

Fixed the linting errors in commit fc4844f. The issue was nested with statements in test_entities.py that needed to be combined per the SIM117 ruff rule. All checks now pass:

• ✅ ruff lint
• ✅ ruff format
• ✅ pyright
• ✅ mypy
• ✅ All 101 tests passing
• ✅ Coverage maintained at 86%

[larohra]

@copilot fix these

[Copilot]

@copilot fix these

Fixed both review comments in commit 5e8244b:

• ✅ Removed COVERAGE_REPORT.md
• ✅ Removed coverage.json
• ✅ All tests still pass (101 passed, 21 skipped)
• ✅ Coverage maintained at 86%

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
TOTAL	20476	3215	84%

report-only-changed-files is enabled. No files were changed during this commit :)

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3944	225 💤	0 ❌	0 🔥	1m 12s ⏱️

[Copilot]

Pull request overview

This PR increases unit test coverage for the agent-framework-azurefunctions Python package to meet/exceed the 85% GA requirement by adding targeted tests for previously uncovered paths in orchestration, entities, request parsing, and custom errors.

Changes:

• Added new unit tests for orchestration helpers (AgentTask.try_set_value) and executor ID generation.
• Added a new test module for _errors.py (IncomingRequestError) and expanded tests around entity execution edge cases.
• Expanded AgentFunctionApp tests to cover request parsing/coercion helpers and various error/validation paths.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 6 comments.

File	Description
python/packages/azurefunctions/tests/test_orchestration.py	Adds coverage for AgentTask exception handling and AzureFunctionsAgentExecutor.generate_unique_id.
python/packages/azurefunctions/tests/test_errors.py	New tests covering IncomingRequestError behavior and status code handling.
python/packages/azurefunctions/tests/test_entities.py	Adds tests for non-dict inputs and event loop edge cases in durable entity execution.
python/packages/azurefunctions/tests/test_app.py	Adds tests for AgentFunctionApp helper methods (parsing, coercion, session/thread id handling) and init validation.