feat(api): POST /api/recipes/[id]/view fuer View-Beacon

Body { profile_id } via zod validiert. FK-Violation (unbekanntes
Profil oder Rezept) wird zu 404 normalisiert. Erfolg liefert 204
ohne Body — fire-and-forget vom Client.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/integration/recipe-views.test.ts

@@ -1,8 +1,32 @@
-import { describe, it, expect } from 'vitest';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
 import { openInMemoryForTest } from '../../src/lib/server/db';
+
+// ---------------------------------------------------------------------------
+// Module-level mock so the POST handler uses the in-memory test DB.
+// Must be declared before any import of the handler itself.
+// ---------------------------------------------------------------------------
+const { testDb } = vi.hoisted(() => ({
+  testDb: { current: null as ReturnType<typeof openInMemoryForTest> | null }
+}));
+
+vi.mock('$lib/server/db', async () => {
+  const actual =
+    await vi.importActual<typeof import('../../src/lib/server/db')>(
+      '../../src/lib/server/db'
+    );
+  return {
+    ...actual,
+    getDb: () => {
+      if (!testDb.current) throw new Error('test DB not initialised');
+      return testDb.current;
+    }
+  };
+});
+
 import { recordView, listViews } from '../../src/lib/server/recipes/views';
 import { createProfile } from '../../src/lib/server/profiles/repository';
 import { listAllRecipesPaginated } from '../../src/lib/server/recipes/search-local';
+import { POST } from '../../src/routes/api/recipes/[id]/view/+server';
 
 function seedRecipe(db: ReturnType<typeof openInMemoryForTest>, title: string): number {
   const r = db
@@ -11,6 +35,14 @@ function seedRecipe(db: ReturnType<typeof openInMemoryForTest>, title: string):
   return r.id;
 }
 
+function mkReq(body: unknown) {
+  return new Request('http://test/api/recipes/1/view', {
+    method: 'POST',
+    headers: { 'content-type': 'application/json' },
+    body: JSON.stringify(body)
+  });
+}
+
 describe('014_recipe_views migration', () => {
   it('creates recipe_view table with expected columns', () => {
     const db = openInMemoryForTest();
@@ -125,3 +157,83 @@ describe("listAllRecipesPaginated sort='viewed'", () => {
     expect(hits.map((h) => h.title)).toEqual(['Apfelkuchen', 'Brokkoli', 'Couscous']);
   });
 });
+
+// ---------------------------------------------------------------------------
+// POST /api/recipes/[id]/view — endpoint integration tests
+// ---------------------------------------------------------------------------
+
+beforeEach(() => {
+  testDb.current = openInMemoryForTest();
+});
+
+describe('POST /api/recipes/[id]/view', () => {
+  it('204 + view row written on success', async () => {
+    const db = testDb.current!;
+    const profile = createProfile(db, 'Tester');
+    const recipeId = seedRecipe(db, 'Pasta');
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const res = await POST({ params: { id: String(recipeId) }, request: mkReq({ profile_id: profile.id }) } as any);
+
+    expect(res.status).toBe(204);
+    const rows = listViews(db, profile.id);
+    expect(rows.length).toBe(1);
+    expect(rows[0].recipe_id).toBe(recipeId);
+  });
+
+  it('400 on recipe id = 0', async () => {
+    await expect(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      POST({ params: { id: '0' }, request: mkReq({ profile_id: 1 }) } as any)
+    ).rejects.toMatchObject({ status: 400 });
+  });
+
+  it('400 on non-numeric recipe id', async () => {
+    await expect(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      POST({ params: { id: 'abc' }, request: mkReq({ profile_id: 1 }) } as any)
+    ).rejects.toMatchObject({ status: 400 });
+  });
+
+  it('400 on missing profile_id in body', async () => {
+    await expect(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      POST({ params: { id: '1' }, request: mkReq({}) } as any)
+    ).rejects.toMatchObject({ status: 400 });
+  });
+
+  it('400 on non-positive profile_id', async () => {
+    await expect(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      POST({ params: { id: '1' }, request: mkReq({ profile_id: 0 }) } as any)
+    ).rejects.toMatchObject({ status: 400 });
+  });
+
+  it('400 on malformed JSON body', async () => {
+    const badReq = new Request('http://test/api/recipes/1/view', {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: 'not-json'
+    });
+    await expect(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      POST({ params: { id: '1' }, request: badReq } as any)
+    ).rejects.toMatchObject({ status: 400 });
+  });
+
+  it('404 on unknown profile_id (FK violation)', async () => {
+    const recipeId = seedRecipe(testDb.current!, 'Pasta');
+    await expect(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      POST({ params: { id: String(recipeId) }, request: mkReq({ profile_id: 999 }) } as any)
+    ).rejects.toMatchObject({ status: 404 });
+  });
+
+  it('404 on unknown recipe_id (FK violation)', async () => {
+    const profile = createProfile(testDb.current!, 'Tester');
+    await expect(
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      POST({ params: { id: '99999' }, request: mkReq({ profile_id: profile.id }) } as any)
+    ).rejects.toMatchObject({ status: 404 });
+  });
+});