fix(tests): P0 test coverage - services & error handler

[devin-ai-integration]

Summary

Addresses the three P0 gaps identified in the test coverage analysis:

1. New HttpErrorHandler tests (error.service.spec.ts) — 6 tests covering all 3 error-handling paths: client-side ErrorEvent, server-side HTTP status codes, and Spring MVC errors header parsing (including edge cases for missing errorMessage and empty arrays).

2. Real HTTP tests for 5 stub-only services — Replaced the expect(service).toBeTruthy() stubs in PetService, VetService, VisitService, SpecialtyService, and PetTypeService with full CRUD test suites (get all, get by id, add, update, delete) using HttpTestingController. Each spec verifies HTTP method, URL, request body, and response handling. addPet and addVisit verify their owner-scoped URL construction.

3. Fixed broken error test in owner.service.spec.ts — The original test had a syntax bug (error assertion was inside the success callback via comma operator) and referenced an httpClientSpy that wasn't wired into the test module. Replaced with a working test that uses HttpTestingController.flush() with a 404 status and subscribes with an error handler.

All 70 tests pass locally. Net change: +723 lines, −236 lines across 7 spec files.

Review & Testing Checklist for Human

• Verify test fixture shapes match actual interfaces — Each spec hardcodes test data (testPet, testVet, testVisit, etc.). Confirm required fields aren't missing and types are correct (e.g., Pet.owner, Visit.pet). TypeScript won't catch mismatches in test data if fields are optional.
• Verify addPet and addVisit URL patterns — These tests assert owner-scoped URLs (owners/{id}/pets, owners/{id}/pets/{id}/visits). Confirm these match the actual service implementations in pet.service.ts and visit.service.ts.
• Check the owner error test assertion strength — expect(errorMsg).toContain('404') is loose. Consider whether an exact match against the HttpErrorHandler output format would be more appropriate.
• Consider whether error-path tests are needed for the 5 new service specs — Only OwnerService has an error-path test. The other 5 services delegate to HttpErrorHandler (now tested separately), but integration-level error tests may still be valuable.

Test plan: Run npx ng test --watch=false --browsers=ChromeHeadless and confirm 70/70 pass. Optionally inspect coverage with npx ng test --code-coverage to confirm the new tests actually hit the service and error handler source lines.

Notes

• The 5 new service specs follow a uniform pattern (copy-paste with adaptations per service). This is intentional — each service has the same CRUD shape — but worth a quick scan to confirm service-specific details (URLs, method signatures like string vs number for ID params) are correct.
• Uses the deprecated subscribe(nextFn, errorFn) signature in the owner error test rather than subscribe({next, error}). This works on the project's current RxJS version but may trigger deprecation warnings on upgrade.

Link to Devin session: https://partner-workshops.devinenterprise.com/sessions/03cc3bd30e654edba1792a712ac25648

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[devin-ai-integration]

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 3 additional findings.

[VedantKh]

you are missing some tests still, resolve other high importance gaps in test coverage