diff --git a/src/index.js b/src/index.js
index d98ef6d..871f187 100644
--- a/src/index.js
+++ b/src/index.js
@@ -25,7 +25,11 @@ const apiDocsRouter = require('./routes/apiDocs');
 const priceWebSocket = require('./ws/priceWebSocket');
 
 const app = express();
-let server;
+let server = {
+  close(callback) {
+    if (callback) callback();
+  },
+};
 
 app.use(requestIdMiddleware);
 app.use(helmet());
@@ -142,6 +146,7 @@ async function startServer() {
   return server;
 }
 
+module.exports = { app, server };
 module.exports = app;
 module.exports.app = app;
 module.exports.server = server || {
diff --git a/test/airdrops.test.js b/test/airdrops.test.js
index d3cc6a6..cda68c9 100644
--- a/test/airdrops.test.js
+++ b/test/airdrops.test.js
@@ -2,6 +2,7 @@
 
 const mockStore = new Map();
 const mockSets = new Map();
+const mockSortedSets = new Map();
 const mockZSets = new Map();
 const mockLists = new Map();
 const mockCounters = new Map();
@@ -16,6 +17,20 @@ const mockRedis = {
     mockSets.get(key)?.delete(val);
   }),
   zadd: jest.fn(async (key, score, member) => {
+    if (!mockSortedSets.has(key)) mockSortedSets.set(key, new Map());
+    mockSortedSets.get(key).set(member, score);
+  }),
+  zrem: jest.fn(async (key, member) => {
+    mockSortedSets.get(key)?.delete(member);
+  }),
+  zcard: jest.fn(async (key) => mockSortedSets.get(key)?.size || 0),
+  zrevrange: jest.fn(async (key, start, stop) => {
+    const sortedSet = mockSortedSets.get(key);
+    if (!sortedSet) return [];
+    const entries = Array.from(sortedSet.entries()).sort((a, b) => b[1] - a[1]);
+    const startIdx = start === -1 ? entries.length + start : start;
+    const stopIdx = stop === -1 ? entries.length + stop : stop;
+    return entries.slice(startIdx, stopIdx + 1).map(([member]) => member);
     if (!mockZSets.has(key)) mockZSets.set(key, new Map());
     mockZSets.get(key).set(member, Number(score));
   }),
@@ -53,7 +68,9 @@ const mockRedis = {
   }),
   lrange: jest.fn(async (key, start, end) => {
     const list = mockLists.get(key) || [];
-    return list.slice(start, end + 1);
+    const startIdx = start === -1 ? list.length + start : start;
+    const endIdx = end === -1 ? list.length + end : end;
+    return list.slice(startIdx, endIdx + 1);
   }),
   incr: jest.fn(async (key) => {
     const count = (mockCounters.get(key) || 0) + 1;
@@ -109,12 +126,14 @@ const config = require('../src/config');
 let app;
 
 beforeAll(() => {
-  app = require('../src/index');
+  const { app: importedApp } = require('../src/index');
+  app = importedApp;
 });
 
 beforeEach(() => {
   mockStore.clear();
   mockSets.clear();
+  mockSortedSets.clear();
   mockZSets.clear();
   mockLists.clear();
   mockCounters.clear();
@@ -126,6 +145,8 @@ beforeEach(() => {
   mockRedis.srem.mockClear();
   mockRedis.zadd.mockClear();
   mockRedis.zrem.mockClear();
+  mockRedis.zcard.mockClear();
+  mockRedis.zrevrange.mockClear();
   mockRedis.zrevrange.mockClear();
   mockRedis.zcard.mockClear();
   mockRedis.zscan.mockClear();
@@ -150,7 +171,7 @@ describe('POST /api/v1/airdrops', () => {
         asset: 'USDC',
         asset_issuer: 'GA5ZSEJYB37JRC5AVCIA5MOP4RHTM335AX2OBFLDTQLNUEHRGPTM6RIA',
         total_amount: 100,
-        expiry_ledger: 123456,
+        expiry_ledger: 123456, // Greater than mockLedger.sequence (12345)
         recipients: [
           { address: validAddress1, amount: 50 },
           { address: validAddress2, amount: 50 },
@@ -204,6 +225,7 @@ describe('POST /api/v1/airdrops', () => {
 
 describe('GET /api/v1/airdrops', () => {
   test('lists airdrops with pagination', async () => {
+    const res1 = await request(app)
     await request(app)
       .post('/api/v1/airdrops')
       .send({
@@ -214,6 +236,7 @@ describe('GET /api/v1/airdrops', () => {
         expiry_ledger: 123456,
       });
 
+    const res2 = await request(app)
     await request(app)
       .post('/api/v1/airdrops')
       .send({
diff --git a/test/alerts-routes.test.js b/test/alerts-routes.test.js
index 6f8ae8b..61aa5e3 100644
--- a/test/alerts-routes.test.js
+++ b/test/alerts-routes.test.js
@@ -3,11 +3,28 @@
 const adminApiKey = 'a'.repeat(64);
 process.env.ADMIN_API_KEY = adminApiKey;
 
+const mockStore = new Map();
+const mockSortedSets = new Map();
 const mockZSets = new Map();
 
 const mockRedis = {
   smembers: jest.fn(async () => []),
   zadd: jest.fn(async (key, score, member) => {
+    if (!mockSortedSets.has(key)) mockSortedSets.set(key, new Map());
+    mockSortedSets.get(key).set(member, score);
+  }),
+  zrem: jest.fn(async (key, member) => {
+    mockSortedSets.get(key)?.delete(member);
+  }),
+  zcard: jest.fn(async (key) => mockSortedSets.get(key)?.size || 0),
+  zrevrange: jest.fn(async (key, start, stop) => {
+    const sortedSet = mockSortedSets.get(key);
+    if (!sortedSet) return [];
+    const entries = Array.from(sortedSet.entries()).sort((a, b) => b[1] - a[1]);
+    const startIdx = start === -1 ? entries.length + start : start;
+    const stopIdx = stop === -1 ? entries.length + stop : stop;
+    return entries.slice(startIdx, stopIdx + 1).map(([member]) => member);
+  }),
     if (!mockZSets.has(key)) mockZSets.set(key, new Map());
     mockZSets.get(key).set(member, Number(score));
   }),
@@ -28,9 +45,9 @@ const mockRedis = {
 
 jest.mock('../src/services/cache', () => ({
   getClient: () => mockRedis,
-  get: jest.fn(),
-  set: jest.fn(),
-  del: jest.fn(),
+  get: jest.fn(async (key) => mockStore.get(key) || null),
+  set: jest.fn(async (key, value) => mockStore.set(key, value)),
+  del: jest.fn(async (key) => mockStore.delete(key)),
   disconnect: jest.fn(),
   isConnected: jest.fn(() => false),
 }));
@@ -46,6 +63,11 @@ const request = require('supertest');
 const { app, server } = require('../src');
 const priceRefreshJob = require('../src/jobs/priceRefresh');
 
+beforeEach(() => {
+  mockStore.clear();
+  mockSortedSets.clear();
+});
+
 
 describe('GET /api/v1/alerts pagination', () => {
 
diff --git a/test/auth.test.js b/test/auth.test.js
index 1252885..d9f2424 100644
--- a/test/auth.test.js
+++ b/test/auth.test.js
@@ -6,6 +6,7 @@ const crypto = require('crypto');
 
 const mockStore = new Map();
 const mockSets = new Map();
+const mockSortedSets = new Map();
 const mockZSets = new Map();
 
 const mockRedis = {
@@ -18,6 +19,19 @@ const mockRedis = {
     mockSets.get(key)?.delete(val);
   }),
   zadd: jest.fn(async (key, score, member) => {
+    if (!mockSortedSets.has(key)) mockSortedSets.set(key, new Map());
+    mockSortedSets.get(key).set(member, score);
+  }),
+  zrem: jest.fn(async (key, member) => {
+    mockSortedSets.get(key)?.delete(member);
+  }),
+  zrevrange: jest.fn(async (key, start, stop) => {
+    const sortedSet = mockSortedSets.get(key);
+    if (!sortedSet) return [];
+    const entries = Array.from(sortedSet.entries()).sort((a, b) => b[1] - a[1]);
+    const startIdx = start === -1 ? entries.length + start : start;
+    const stopIdx = stop === -1 ? entries.length + stop : stop;
+    return entries.slice(startIdx, stopIdx + 1).map(([member]) => member);
     if (!mockZSets.has(key)) mockZSets.set(key, new Map());
     mockZSets.get(key).set(member, Number(score));
   }),
@@ -85,12 +99,16 @@ function buildKeysApp() {
 beforeEach(() => {
   mockStore.clear();
   mockSets.clear();
+  mockSortedSets.clear();
   cache.get.mockClear();
   cache.set.mockClear();
   cache.del.mockClear();
   mockRedis.smembers.mockClear();
   mockRedis.sadd.mockClear();
   mockRedis.srem.mockClear();
+  mockRedis.zadd.mockClear();
+  mockRedis.zrem.mockClear();
+  mockRedis.zrevrange.mockClear();
 });
 
 describe('requireApiKey middleware', () => {