test: Achieve 80% unit test coverage across lib/translator/ and add contract blueprint validation tests

[grantfox-oss]

Body:
Summary
The Translation Registry in lib/translator/ is the most critical part of Open-Audit — it is responsible for converting raw Stellar XDR events into human-readable output. Despite its importance, test coverage for this module is incomplete, and there are no automated tests that validate the correctness of community-contributed blueprints in lib/translator/blueprints/. This creates a risk that broken translations get merged and silently produce incorrect output.
Required work

1. Unit tests for lib/translator/registry.ts — covering:

Known contract ID returns the correct blueprint
Unknown contract ID returns a graceful fallback (untranslated raw event, no throw)
Blueprint template interpolation with all supported field types (address, amount, asset code, timestamp)
Malformed XDR input is handled without crashing
Translation output matches the exact string format documented in CONTRIBUTING.md

2. Unit tests for lib/translator/secure-xdr-parser.ts — covering:

Valid XDR hex returns { success: true, value: ... }
Deeply nested XDR (depth > MAX) returns { success: false } with a descriptive error
Oversized payload (> 10MB) is rejected before parsing begins
Parsing timeout fires correctly for an intentionally slow mock
Each ScVal type (address, int128, string, bool, vec, map) parses to its expected output

3. Blueprint schema validation tests — for every file in lib/translator/blueprints/:

Each blueprint exports the required fields: contractId, events (array), each event has topic, template, and fields
Field references in template (e.g. {from}, {amount}) all exist in the fields array — no dangling references
No two blueprints register the same contractId
Run this as a Vitest test so CI catches invalid blueprints on every PR

4. Add a coverage threshold to vitest.config.ts:
   tscoverage: {
   thresholds: {
   'lib/translator/**': { lines: 80, functions: 80, branches: 75 }
   }
   }
   Acceptance criteria

npm test passes with coverage ≥ 80% lines and functions across lib/translator/
Blueprint validation test catches a deliberately broken blueprint (add one as a fixture, assert the test fails, then remove it)
All existing tests continue to pass
CI workflow runs coverage check and fails the build if threshold is not met

[gloskull]

Hi, I’d love to work on this issue. I have 4 years of experience across backend, frontend, full-stack, and smart contract development. I understand the task clearly and can deliver a clean, efficient, well-tested solution on time, with strong focus on code quality and maintainability. My PR will be submitted in under 10 hours.

[clintjeff2]

Hello, I have 6 years of experience working on tasks like this and handling similar challenges across backend, frontend, and smart-contract development. I have carefully read and fully understood the task requirements, and I am confident I can deliver a clean, efficient, and well-tested solution promptly. I always ensure high-quality implementation, maintainability, and adherence to best practices.

Pull request in 5 hours.

[skaichima]

I'm interested in working on this issue. I have the necessary skills to handle this efficiently and would appreciate it if you could assign it to me. Thanks!

[modest12345678]

Hi team 👋

I'd like to apply to this issue.

Motivation

The Translation Registry is the heart of Open-Audit — if it silently produces wrong output, everything downstream is corrupted. I've worked in codebases where missing test coverage on a critical translation layer caused production bugs that were nearly impossible to trace. Reaching 80% coverage here and adding automated blueprint schema validation will give every future contributor instant feedback that their blueprint is structurally correct before it ever reaches a reviewer.

What I'll build

I've already studied registry.ts, secure-xdr-parser.ts, and the two existing blueprints (sac-transfer.ts, sac-mint-burn.ts). Here's my plan:

1. lib/translator/tests/registry.test.ts — covering:

Known contract ID (SAC USDC/XLM/EURC) returns the correct blueprint and status: "translated"
Unknown contract ID returns status: "cryptic" with no throw — graceful fallback via decodeGenericEventPayload
Template interpolation for all field types: address ({from}, {to}), amount ({amount} as i128 → human-readable), asset code, timestamp
Malformed XDR data/topics (null, empty string, non-hex) handled without crashing
Versioned blueprint selection: two schemas for the same contractId with different validFromLedger values; the correct schema chosen per ledger number
translateWithCache: mocks getCachedTranslation/setCachedTranslation to verify caching branch
2. Extended secure-xdr-parser.test.ts — covering every ScVal type:

scvAddress, scvI128, scvString, scvBool, scvVec, scvMap all parse to { success: true }
Deeply nested XDR (depth > MAX) → { success: false } with "depth" in error message
Payload > 10 MB rejected before parsing begins (fast path in validateHexLength)
Timeout: mock checkTimeout to throw → { success: false } with "timeout" in error
Garbled/empty hex → { success: false }
3. lib/translator/tests/blueprint-validation.test.ts — Vitest CI gate for all blueprints:

Dynamically imports every *.ts file in lib/translator/blueprints/
Asserts: contractId, contractName, events[] present; each event has topic, template, fields
Detects dangling {placeholder} references by diffing template tokens against fields[].name
Asserts no two blueprints share the same contractId
Validates field.type is one of the allowed enum values
Includes a broken blueprint fixture (fixtures/broken-blueprint.fixture.ts) with deliberate dangling references — test asserts it fails validation, proving the guard works
4. vitest.config.ts — adds:

ts

coverage: {
provider: "v8",
include: ["lib/translator/"],
thresholds: {
"lib/translator/": { lines: 80, functions: 80, branches: 75 }
}
}
Experience

I have strong experience with:

Vitest (vi.mock, vi.spyOn, fake timers for timeout tests, coverage thresholds)
Stellar SDK XDR encoding/decoding (ScVal, xdr.fromXDR)
Writing schema validation tests that catch structural errors at CI time
Mocking Redis cache layers cleanly without real connections
Timeline

Complete PR with all three test suites, the broken fixture, vitest.config.ts update, and no regressions — within 3–4 days of assignment.

Looking forward to strengthening the test foundation for Open-Audit! 🚀