test: add unit tests for TransactionStatusCheckerProcessor and LoanPaymentReminderProcessor

[Josue19-08]

🔖 Title

Add unit tests for `TransactionStatusCheckerProcessor` and `LoanPaymentReminderProcessor`

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📄 Description

`test/unit/jobs/` contains only `blockchain-indexer.processor.spec.ts`. Two other job processors with significant business logic are completely untested:

`TransactionStatusCheckerProcessor` — critical paths with no test coverage:

• Horizon retry with exponential back-off (transient errors silently swallowed if retries exhausted)
• `parseTransactionMetadata()` — parses raw Stellar XDR to extract `loanId` and `amount` from `invokeHostFunction` operations; a parsing bug here silently misapplies payments to wrong loans
• `activatePendingLoan()` and `applyLoanRepayment()` — DB mutations triggered by XDR parse result
• Notification creation on loan activation and repayment
• `cleanupOldTransactions()` scheduled deletion

`LoanPaymentReminderProcessor` — date-boundary logic with no test coverage:

• 3-day reminder window calculation
• 1-day reminder window calculation
• Overdue detection
• Duplicate notification skip (same loan, same window, reminder already sent)

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✅ Tasks to complete

• Create `test/unit/jobs/transaction-status-checker/transaction-status-checker.processor.spec.ts`:
  • Successful `create_loan` XDR → loan activated, notification created
  • Successful `repay_loan` XDR → repayment applied, reputation update triggered
  • Horizon transient error → retries up to max; logs warning; does not throw
  • Horizon 404 (not found) → transaction marked as failed gracefully
  • XDR parse failure → processor logs error, does not crash, marks transaction failed
  • `cleanupOldTransactions()` → calls repository delete with correct cutoff date
• Create `test/unit/jobs/loan-payment-reminder/loan-payment-reminder.processor.spec.ts`:
  • Loan due in 3 days → 3-day reminder notification created
  • Loan due in 1 day → 1-day reminder notification created
  • Loan overdue → overdue notification created
  • Loan with reminder already sent for that window → no duplicate notification
  • Loan already completed → skipped
• Create `test/fixtures/jobs.fixtures.ts` — add typed fixtures: pending transactions, sample XDR for `invokeHostFunction`, active loans with due dates at various offsets
• Create or extend `test/helpers/` — add BullMQ `Job` mock factory and Supabase query chain mock
• Refactor `src/jobs/transaction-status-checker/transaction-status-checker.processor.ts` — export `parseTransactionMetadata` as `protected` (or extract to a pure utility function) to enable isolated unit testing without running the full processor
• Refactor `src/jobs/loan-payment-reminder/loan-payment-reminder.processor.ts` — extract date-window calculation into a pure function `getReminderWindow(dueDate: Date, now: Date): 'three-day' | 'one-day' | 'overdue' | null` for isolated testing

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📚 Documentation/context for AI

(This link never should removed)
https://github.com/TrustUp-app/TrustUp-API/tree/main/docs

Relevant files:

• `src/jobs/transaction-status-checker/transaction-status-checker.processor.ts`
• `src/jobs/loan-payment-reminder/loan-payment-reminder.processor.ts`
• `test/unit/jobs/blockchain-indexer.processor.spec.ts` — use as pattern reference
• `test/fixtures/`
• `test/helpers/`

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🗒️ Additional notes

• Use `jest.useFakeTimers()` for date-sensitive tests in the reminder processor to control `new Date()` without flakiness
• XDR fixtures can be generated via `StellarSdk.xdr` in a test setup script — commit the base64 string directly to `test/fixtures/` to avoid SDK calls in tests
• BullMQ `Job` mock only needs `id`, `name`, and `data` fields for these processors
• The `parseTransactionMetadata` extraction should not change public API — it is an internal refactor for testability only

[shepherd-001]

Hello, I have reviewed this issue and am confident I can resolve it. Please assign this task to me.

[SudiptaPaul-31]

Hey Maintainer!!! My name is Sudipta Paul a very old contributor of GrantFox and other platform having quite a lot of experience in open source and working with full stack issues as well as very much proficient in writing contracts and would love to work on this issue and contribute to your project, May I be assigned to this task