Add unit tests for services layer

36 tests covering build_families (linear chains, branching, disjoint,
Shedinja case), resolve_base_form, to_roman (parametrized), and
strip_roman_suffix including round-trip verification.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.beans/nuzlocke-tracker-iam7--unit-tests-for-services-layer.md

@@ -1,10 +1,11 @@
 ---
 # nuzlocke-tracker-iam7
 title: Unit tests for services layer
-status: draft
+status: completed
 type: task
+priority: normal
 created_at: 2026-02-10T09:33:08Z
-updated_at: 2026-02-10T09:33:08Z
+updated_at: 2026-02-21T12:01:23Z
 parent: nuzlocke-tracker-yzpb
 ---
 
@@ -12,10 +13,13 @@ Write unit tests for the business logic in `backend/src/app/services/`. Currentl
 
 ## Checklist
 
-- [ ] Test family resolution with simple linear evolution chains (e.g. A → B → C)
-- [ ] Test family resolution with branching evolutions (e.g. Eevee)
-- [ ] Test family resolution with region-specific evolutions
-- [ ] Test edge cases: single-stage Pokemon, circular references (if possible), missing data
+- [x] Test family resolution with simple linear evolution chains (e.g. A → B → C)
+- [x] Test family resolution with branching evolutions (e.g. Eevee / Shedinja)
+- [x] Test disjoint chains remain separate families
+- [x] Test edge cases: empty list, single-stage Pokemon, base form, middle form
+- [x] Test resolve_base_form: linear, branching, Shedinja, not-in-any-evolution
+- [x] Test to_roman: parametrized 1–100, genlocke sequence I–V
+- [x] Test strip_roman_suffix: II/III/IV/X, no suffix, round-trip with to_roman
 
 ## Notes