Verbessere die Berechnung der Geschenkekosten in FalukantService und füge Tests für die Funktion hinzu

backend/tools/testGiftCost.js

@@ -0,0 +1,38 @@
+import { fileURLToPath } from 'url';
+import path from 'path';
+import { readFileSync } from 'fs';
+
+// Kleine Testhilfe: extrahiere getGiftCost aus service-file via eval (schneller Smoke-test ohne DB)
+const svcPath = path.resolve(process.cwd(), 'services', 'falukantService.js');
+const src = readFileSync(svcPath, 'utf8');
+
+// Extrahiere die getGiftCost-Funktion via Regex (vereinfachte Annahme)
+const re = /async getGiftCost\([\s\S]*?\n\s*}\n/;
+const match = src.match(re);
+if (!match) {
+  console.error('getGiftCost function not found');
+  process.exit(2);
+}
+const funcSrc = match[0];
+// Wrappe in Async-Function und erzeuge getGiftCost im lokalen Scope
+const wrapper = `(async () => { ${funcSrc}; return getGiftCost; })()`;
+// eslint-disable-next-line no-eval
+const getGiftCostPromise = eval(wrapper);
+let getGiftCost;
+getGiftCostPromise.then(f => { getGiftCost = f; runTests(); }).catch(e => { console.error('eval failed', e); process.exit(2); });
+
+function runTests() {
+  const cases = [
+    { value: 100, title: 3, lowest: 1 },
+    { value: '200', title: '2', lowest: '1' },
+    { value: null, title: null, lowest: null },
+    { value: 'abc', title: 5, lowest: 1 }
+  ];
+
+  for (const c of cases) {
+    getGiftCost(c.value, c.title, c.lowest).then(out => {
+      console.log(`in=${JSON.stringify(c)} -> cost=${out}`);
+    }).catch(err => console.error('error calling getGiftCost', err));
+  }
+}
+// Ende Patch