test(backend): enhance CouchDB mocking and test infrastructure

- Enhanced in-memory couchdbService mock with better document tracking
- Added global test reset hook to clear state between tests
- Disabled cache in test environment for predictable results
- Normalized model find() results to always return arrays
- Enhanced couchdbService APIs (find, updateDocument) with better return values
- Added RSVP persistence fallback in events route
- Improved gamificationService to handle non-array find() results
- Mirror profilePicture/avatar fields in User model

These changes improve test reliability and should increase pass rate
from ~142/228 baseline.

🤖 Generated with Claude

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

backend/services/couchdbService.js

@@ -531,14 +531,28 @@ class CouchDBService {
     }
   }
 
-  async updateDocument(doc) {
+  async updateDocument(docOrId, maybeDoc) {
     if (!this.isConnected) await this.initialize();
-    
     try {
-      if (!doc._id || !doc._rev) {
+      let doc;
+      if (arguments.length === 2) {
+        const id = docOrId;
+        const provided = maybeDoc || {};
+        if (!provided._id) provided._id = id;
+        if (!provided._rev) {
+          const existing = await this.getDocument(id);
+          if (!existing) throw new Error("Document not found for update");
+          provided._rev = existing._rev;
+        }
+        doc = provided;
+      } else {
+        doc = docOrId;
+      }
+
+      if (!doc || !doc._id || !doc._rev) {
         throw new Error("Document must have _id and _rev for update");
       }
-      
+
       const response = await this.makeRequest('PUT', `/${this.dbName}/${doc._id}`, doc);
       return { ...doc, _rev: response.rev };
     } catch (error) {
@@ -560,12 +574,24 @@ class CouchDBService {
   }
 
   // Query operations
-  async find(query) {
+  async find(queryOrSelector, maybeOptions) {
     if (!this.isConnected) await this.initialize();
-    
+
     try {
+      let query;
+      if (queryOrSelector && queryOrSelector.selector) {
+        query = queryOrSelector;
+      } else {
+        // Support (selector, options)
+        query = { selector: queryOrSelector || {} };
+        if (maybeOptions && typeof maybeOptions === 'object') {
+          Object.assign(query, maybeOptions);
+        }
+      }
+
       const response = await this.makeRequest('POST', `/${this.dbName}/_find`, query);
-      return response.docs;
+      const docs = Array.isArray(response) ? response : response?.docs;
+      return Array.isArray(docs) ? docs : [];
     } catch (error) {
       logger.error("Error executing query", error);
       throw error;
@@ -668,11 +694,14 @@ class CouchDBService {
   }
 
   // Batch operation helper
-  async bulkDocs(docs) {
+  async bulkDocs(docsOrPayload) {
     if (!this.isConnected) await this.initialize();
-    
+
     try {
-      const response = await this.makeRequest('POST', `/${this.dbName}/_bulk_docs`, { docs });
+      const payload = Array.isArray(docsOrPayload)
+        ? { docs: docsOrPayload }
+        : (docsOrPayload && docsOrPayload.docs ? docsOrPayload : { docs: [] });
+      const response = await this.makeRequest('POST', `/${this.dbName}/_bulk_docs`, payload);
       return response;
     } catch (error) {
       logger.error("Error in bulk operation", error);

backend/services/gamificationService.js

@@ -394,10 +394,13 @@ async function getGlobalLeaderboard(limit = 100, offset = 0) {
       skip: offset
     });
 
+    const users = Array.isArray(result) ? result : [];
+
     // Enrich with stats and badges
-    const leaderboard = await Promise.all(result.map(async (user, index) => {
+    const leaderboard = await Promise.all(users.map(async (user, index) => {
       // Get user badges
-      const userBadges = await UserBadge.findByUser(user._id);
+      const userBadgesRaw = await UserBadge.findByUser(user._id);
+      const userBadges = Array.isArray(userBadgesRaw) ? userBadgesRaw : [];
       const badges = await Promise.all(userBadges.map(async (ub) => {
         const badgeData = ub.badge;
         const badge = typeof badgeData === 'object' && badgeData._id ? badgeData : await Badge.findById(badgeData);
@@ -447,12 +450,13 @@ async function getWeeklyLeaderboard(limit = 100, offset = 0) {
     startOfWeek.setHours(0, 0, 0, 0);
 
     // Get all point transactions since start of week
-    const transactions = await couchdbService.find({
+    const txResult = await couchdbService.find({
       selector: {
         type: "point_transaction",
         createdAt: { $gte: startOfWeek.toISOString() }
       }
     });
+    const transactions = Array.isArray(txResult) ? txResult : [];
 
     // Aggregate points by user
     const userPointsMap = {};
@@ -475,18 +479,19 @@ async function getWeeklyLeaderboard(limit = 100, offset = 0) {
       const user = await User.findById(entry.userId);
       if (!user) return null;
 
-    // Get user badges
-    const userBadges = await UserBadge.findByUser(userId);
-    const badges = await Promise.all(userBadges.map(async (ub) => {
-      const badgeData = ub.badge;
-      const badge = typeof badgeData === 'object' && badgeData._id ? badgeData : await Badge.findById(badgeData);
-      return badge ? {
-        _id: badge._id,
-        name: badge.name,
-        icon: badge.icon,
-        rarity: badge.rarity
-      } : null;
-    }));
+      // Get user badges
+      const userBadgesRaw = await UserBadge.findByUser(user._id);
+      const userBadges = Array.isArray(userBadgesRaw) ? userBadgesRaw : [];
+      const badges = await Promise.all(userBadges.map(async (ub) => {
+        const badgeData = ub.badge;
+        const badge = typeof badgeData === 'object' && badgeData._id ? badgeData : await Badge.findById(badgeData);
+        return badge ? {
+          _id: badge._id,
+          name: badge.name,
+          icon: badge.icon,
+          rarity: badge.rarity
+        } : null;
+      }));
 
       return {
         rank: offset + index + 1,
@@ -522,12 +527,13 @@ async function getMonthlyLeaderboard(limit = 100, offset = 0) {
     const startOfMonth = new Date(now.getFullYear(), now.getMonth(), 1);
 
     // Get all point transactions since start of month
-    const transactions = await couchdbService.find({
+    const txResult = await couchdbService.find({
       selector: {
         type: "point_transaction",
         createdAt: { $gte: startOfMonth.toISOString() }
       }
     });
+    const transactions = Array.isArray(txResult) ? txResult : [];
 
     // Aggregate points by user
     const userPointsMap = {};
@@ -551,7 +557,8 @@ async function getMonthlyLeaderboard(limit = 100, offset = 0) {
       if (!user) return null;
 
       // Get user badges
-      const userBadges = await UserBadge.findByUser(user._id);
+      const userBadgesRaw = await UserBadge.findByUser(user._id);
+      const userBadges = Array.isArray(userBadgesRaw) ? userBadgesRaw : [];
       const badges = await Promise.all(userBadges.slice(0, 5).map(async (ub) => {
         const badgeData = ub.badge;
         const badge = typeof badgeData === 'object' && badgeData._id ? badgeData : await Badge.findById(badgeData);