test: add unit tests for DuplicateService (Fixes #442)

[zeroknowledge0x]

Fixes #442

Summary

Adds comprehensive unit tests for DuplicateService in backend/services/duplicate_service.py. All 25 tests pass with ML dependencies mocked.

Changes

• Created backend/tests/test_duplicate_service.py with 25 test cases
• Covers all public methods: is_available(), load(), add_ticket(), check_duplicate(), save_to_disk()
• Tests initialization state, availability flags, memory persistence, disk persistence
• Tests duplicate detection with configurable thresholds
• Tests graceful degradation when model is unavailable
• Tests corrupt JSON handling in storage file

Testing

python -m pytest backend/tests/test_duplicate_service.py -v

Result: 25 passed in 8.35s

Test Coverage

Category	Tests	Description
Init	2	Default state, storage dir creation
is_available	4	Not loaded, loaded, failed, loaded+failed
add_ticket	4	Memory, disk, multiple, degraded skip
check_duplicate	6	No tickets, degraded, above threshold, below threshold, custom threshold, best match
save_to_disk	4	New file, append, corrupt JSON, non-list JSON
load	5	Flag set, idempotent, failure flag, degraded startup, load saved tickets

All ML dependencies (sentence_transformers) are mocked — no model download required.

Summary by CodeRabbit

• Tests
  • Added comprehensive test suite for duplicate detection service, covering initialization, availability checks, ticket management, disk persistence, and model loading to ensure system reliability and robustness.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: b07e0e89-5d92-49ce-9961-5645010e80f9

📥 Commits

Reviewing files that changed from the base of the PR and between 1c5fccf and 77a77c3.

📒 Files selected for processing (1)

• backend/tests/test_duplicate_service.py

📝 Walkthrough

Walkthrough

A complete pytest test suite for DuplicateService covering initialization state, availability checks, ticket addition and in-memory/disk persistence, duplicate detection with similarity thresholding and best-match selection, cache recovery from corrupt JSON, model loading with idempotency and failure flagging, and degraded startup mode via environment variable.

Changes

DuplicateService Unit Tests

Layer / File(s)	Summary
Test fixtures and infrastructure backend/tests/test_duplicate_service.py	Module imports for json/os/tempfile/pytest/unittest.mock and three pytest fixtures: _no_model_imports stubs heavy sentence_transformers imports; service creates a fresh DuplicateService wired to a temp cache file; loaded_service provides a preloaded service with mocked model and encoded tensor-like output.
Service initialization and availability checks backend/tests/test_duplicate_service.py	TestInit verifies default _loaded/_load_failed flags, empty _tickets list, and storage directory creation. TestIsAvailable asserts is_available() returns correct boolean based on combinations of loaded/failed state.
Duplicate detection core logic backend/tests/test_duplicate_service.py	TestCheckDuplicate covers no stored tickets, degraded mode returns, similarity above/below/custom threshold, and best-match selection among multiple tickets using mocked cosine similarity values.
Ticket addition, persistence, and recovery backend/tests/test_duplicate_service.py	TestAddTicket verifies in-memory append and disk persistence in JSON format, and degraded mode skips embedding. TestSaveToDisk handles cache creation, append, and recovery from invalid/non-list JSON. TestLoad verifies _loaded flag setting, idempotent initialization, _load_failed marking on failure, degraded startup via ALLOW_DEGRADED_STARTUP=1 environment variable, and ticket restoration from on-disk cache.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~22 minutes

Possibly related issues

• #297: Tests cover check_duplicate behavior including threshold override, empty store, and degraded mode scenarios.

Possibly related PRs

• ritesh-1918/HELPDESK.AI#509: Both PRs add/extend pytest coverage for DuplicateService targeting backend/tests/test_duplicate_service.py with overlapping test scenarios.
• ritesh-1918/HELPDESK.AI#779: Expands backend/tests/test_duplicate_service.py coverage with continued focus on check_duplicate thresholding, best-match selection, and degraded mode handling.
• ritesh-1918/HELPDESK.AI#551: Extends the same test file coverage for DuplicateService initialization, is_available, degraded mode, and disk persistence logic.

Suggested labels

gssoc, gssoc:approved, level:intermediate, quality:exceptional, type:testing

Poem

🐰 A test suite hops into the warren so fine,
DuplicateService checks—each case does align,
From init to thresholds, persistence so deep,
The tests ensure tickets don't duplicate sheep! 🐑

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 35.71% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'test: add unit tests for DuplicateService' clearly and concisely summarizes the main change—adding comprehensive test coverage for the DuplicateService class.
Linked Issues check	✅ Passed	All coding objectives from issue #442 are met: the test file is created, similarity threshold handling is tested, duplicate detection accuracy is covered, and edge cases including degraded mode and corrupt JSON are properly tested.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to adding unit tests for DuplicateService as required by issue #442; no unrelated modifications are present.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@backend/tests/test_duplicate_service.py`:
- Around line 61-62: The test_storage_dir_created test is tautological because
the service fixture already sets service.storage_file under tmp_path (which
exists); change the test to configure DuplicateService to use a nested,
non-existent path before constructing it so __init__ must create the parent dir,
then assert that target.parent (the directory) exists; locate the
test_storage_dir_created and the service fixture setup (and
DuplicateService.__init__ / storage_file usage) and modify the test to provide a
nested path (e.g. tmp_path / "nested" / "case_history_cache.json") and
instantiate the service so the assertion verifies directory creation rather than
relying on tmp_path.
- Around line 128-132: Remove the leftover variable assignment (drop
loaded_service_result) and make the test actually exercise the degraded path by
adding a stored ticket before calling service.check_duplicate; specifically, in
test_degraded_returns_no_duplicate set service._loaded = False and
service._load_failed = True, store a ticket via the same API used in other tests
(e.g., the service method that adds tickets or the fixture helper) so
check_duplicate would normally detect a duplicate, then call
service.check_duplicate("text") and assert result["is_duplicate"] is False; keep
references to test_degraded_returns_no_duplicate, service._loaded,
service._load_failed, and service.check_duplicate to locate the change.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: a49fdabd-d843-4408-b886-e0acf4aa9faa

📥 Commits

Reviewing files that changed from the base of the PR and between da8faf2 and 1c5fccf.

📒 Files selected for processing (1)

• backend/tests/test_duplicate_service.py

[ritesh-1918]

Hi @zeroknowledge0x! 🙌

Thank you so much for your excellent contribution: "test: add unit tests for DuplicateService (Fixes #442)"! We really appreciate the high-quality code and effort you have put into the platform.

Just a quick, friendly heads-up as we prepare our manual merging and verification queues—please make sure to complete all the mandatory community steps listed below.

Once those manual steps are verified, we'll get your PR officially merged into the gssoc branch (or keep it neatly cataloged if closed as integrated) and assign it the highest possible GSSoC S-Tier labels to maximize your leaderboard points!

Let's build something amazing together! 🚀🔥

---

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[ritesh-1918]

Hi @zeroknowledge0x! 🙌

Thank you so much for your excellent contribution: "test: add unit tests for DuplicateService (Fixes #442)"! We really appreciate the high-quality code and effort you have put into the platform.

Just a quick, friendly heads-up as we prepare our manual merging and verification queues—please make sure to complete all the mandatory community steps listed below.

Once those manual steps are verified, we'll get your PR officially merged into the gssoc branch (or keep it neatly cataloged if closed as integrated) and assign it the highest possible GSSoC S-Tier labels to maximize your leaderboard points!

Let's build something amazing together! 🚀🔥

---

🌟 Community Support & Network Steps (Take 10 Seconds!)

As we prepare our manual verification and merging queues, please make sure you have taken a moment to complete these required steps to finalize your points:

1. ⭐ Star this repository: https://github.com/ritesh-1918/HELPDESK.AI (Mandatory)
2. 🍴 Fork this repository: https://github.com/ritesh-1918/HELPDESK.AI/fork (Mandatory)
3. 👤 Follow @ritesh-1918 on GitHub: https://github.com/ritesh-1918 (Mandatory - manual step)
4. 💼 Connect on LinkedIn: https://www.linkedin.com/in/ritesh1908/ (Mandatory)

Note: Having these steps completed manually is required before your PR points are officially cleared.