test(analytics-api): unit tests for pure-logic modules (threshold/query/metric/config)

[SharedQA]

Raises analytics-api unit coverage on the pure-logic modules (the part that doesn't need a DB/runtime).

Measured (cargo-llvm-cov, instrumented)

• Workspace: 58.53% → 59.86% lines (+1.33pts) from these tests. (api-gateway's larger jump is separate — test(api-gateway): unit tests for OIDC auth-config + CLI (crate ~0%→71%) #1327.)
• threshold.rs 0% → covered; query.rs/metric.rs/config.rs raised.
• 19 tests; analytics-api 257 pass; clippy --all-targets clean (no unwrap/expect in tests).

Test validity

Expected values are derived from documented intent — OData semantics, the in-code PATCH triple-state comment, the default_* fns — not from running the code. Negative/boundary cases included (unknown operator, missing required config, null-vs-absent PATCH, empty/oversized inputs).

One unit was found semantically suspect during review and flagged rather than locked in: threshold_matches's eq uses f64::EPSILON (magnitude-dependent equality) — see #1332. The test characterises current behaviour; the issue asks for the intended rule.

Coverage ceiling

Further unit gains are limited: the remaining uncovered analytics-api/oidc/clickhouse code is runtime/IO (validate_token needs JWKS, DB clients need ClickHouse/MariaDB, main/module wiring need the modkit runtime). Reaching ~80% requires the instrumented e2e profile (the rig running instrumented binaries — milestone 2.15), not more unit tests.

Related correctness findings from this pass: #1330 (duplicate/unstable data), #1331 (time formats), #1332 (threshold eq).

Summary by CodeRabbit

• Tests
  • Added unit test coverage for analytics configuration precedence and required-field validation.
  • Added serialization/deserialization tests for metric update PATCH semantics and query/batch request behavior, including defaulting and JSON status formatting.
  • Added threshold evaluation and request deserialization tests covering supported operators, epsilon equality, invalid operator/level handling, and partial updates.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 7686f291-15ed-4952-b3c6-2d3d81eb1c72

📥 Commits

Reviewing files that changed from the base of the PR and between 231ac7a and 188936b.

📒 Files selected for processing (3)

• src/backend/services/analytics-api/src/config.rs
• src/backend/services/analytics-api/src/domain/metric.rs
• src/backend/services/analytics-api/src/domain/query.rs

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📝 Walkthrough

Walkthrough

Adds #[cfg(test)] modules to four files in the analytics-api service: config.rs, domain/metric.rs, domain/query.rs, and domain/threshold.rs. No production logic is modified; only test coverage is introduced for configuration defaults, serde contracts, and threshold evaluation.

Changes

Analytics API Unit Test Coverage

Layer / File(s)	Summary
AppConfig defaulting and Figment extraction tests src/backend/services/analytics-api/src/config.rs	Tests verify that bind_addr and clickhouse_database can be overridden via inline YAML, and that extraction fails when the required clickhouse_url field is omitted.
Metric domain serde tests src/backend/services/analytics-api/src/domain/metric.rs	Tests validate UpdateMetricRequest.description triple-state deserialization: absent field yields None, explicit null yields Some(None), and provided string yields Some(Some(value)).
Query and batch domain serde tests src/backend/services/analytics-api/src/domain/query.rs	Tests validate OData field mapping ($filter, $orderby, $select, $top, $skip) into QueryRequest, default top value application on empty body, BatchQueryRequest nested deserialization with per-item query payload propagation, and BatchQueryResult::Ok lowercase "status" tag serialization.
Threshold evaluation and request deserialization tests src/backend/services/analytics-api/src/domain/threshold.rs	Tests verify threshold_matches correctly evaluates all supported operators (gt, ge, lt, le, eq) with epsilon tolerance for floating-point equality, rejects unknown and case-mismatched operators, validate VALID_OPERATORS and VALID_LEVELS constant contents and their corresponding invalid-message text, and test CreateThresholdRequest and UpdateThresholdRequest JSON deserialization.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Suggested reviewers

• cyberantonz

Poem

🐇 Hop, hop, hip hooray!
I tested configs today—
Defaults checked and thresholds true,
Serde contracts all shine through.
No null shall slip away! 🎉

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately and clearly summarizes the main change: adding unit tests for four specific pure-logic modules (threshold, query, metric, config) in the analytics-api service.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[SharedQA]

Overlaps #1314 (migrate to gears) on domain/query.rs. Reconcile these unit tests with the gears changes once #1314 merges.

[cyberantonz]

Needs work

[ktursunov]

Already covered with unit tests coverage