ably · ttypic · May 5, 2026
diff --git a/test/uts/helpers.ts b/test/uts/helpers.ts
@@ -14,6 +14,8 @@ import { DefaultRest } from '../../src/common/lib/client/defaultrest';
 import { DefaultRealtime } from '../../src/common/lib/client/defaultrealtime';
 import ErrorInfo from '../../src/common/lib/types/errorinfo';
 import { makeFromDeserializedWithDependencies as makeProtocolMessageFromDeserialized } from '../../src/common/lib/types/protocolmessage';
+import { IPlatformHttpStatic } from '../../src/common/types/http';
+import { IPlatformConfig } from '../../src/common/types/IPlatformConfig';
 
 const Ably = {
   Rest: DefaultRest,
@@ -24,21 +26,23 @@ const Ably = {
 
 const Platform = DefaultRest.Platform;
 
+type Http = typeof Platform.Http; // = IPlatformHttpStatic
+
 // Saved originals for teardown
-let _savedHttp: any = null;
-let _savedWebSocket: any = null;
-let _savedSetTimeout: any = null;
-let _savedClearTimeout: any = null;
-let _savedNow: any = null;
+let _savedHttp: Http | null = null;
+let _savedWebSocket: IPlatformConfig['WebSocket'] | null = null;
+let _savedSetTimeout: IPlatformConfig['setTimeout'] | null = null;
+let _savedClearTimeout: IPlatformConfig['clearTimeout'] | null = null;
+let _savedNow: IPlatformConfig['now'] | null = null;
 
 // Tracked clients for cleanup — ensures timers are released even if a test crashes
-const _trackedClients: any[] = [];
+const _trackedClients: (DefaultRest | DefaultRealtime)[] = [];
 
 /**
  * Install a MockHttpClient as the platform HTTP implementation.
  * Call uninstallMockHttp() in afterEach to restore the original.
  */
-function installMockHttp(mockHttpClient: { asPlatformHttp(): any }): void {
+function installMockHttp(mockHttpClient: { asPlatformHttp(): IPlatformHttpStatic }): void {
   if (_savedHttp) throw new Error('Mock HTTP already installed — call uninstallMockHttp() first');
   _savedHttp = Platform.Http;
   Platform.Http = mockHttpClient.asPlatformHttp();
@@ -58,7 +62,7 @@ function uninstallMockHttp(): void {
  * Install a mock WebSocket constructor.
  * Call uninstallMockWebSocket() in afterEach to restore the original.
  */
-function installMockWebSocket(mockWsConstructor: any): void {
+function installMockWebSocket(mockWsConstructor: IPlatformConfig['WebSocket']): void {
   if (_savedWebSocket) throw new Error('Mock WebSocket already installed');
   _savedWebSocket = Platform.Config.WebSocket;
   Platform.Config.WebSocket = mockWsConstructor;
@@ -175,8 +179,8 @@ class FakeClock {
   uninstall(): void {
     if (_savedSetTimeout) {
       Platform.Config.setTimeout = _savedSetTimeout;
-      Platform.Config.clearTimeout = _savedClearTimeout;
-      Platform.Config.now = _savedNow;
+      Platform.Config.clearTimeout = _savedClearTimeout!;
+      Platform.Config.now = _savedNow!;
       _savedSetTimeout = null;
       _savedClearTimeout = null;
       _savedNow = null;
@@ -202,7 +206,7 @@ function enableFakeTimers(): FakeClock {
  * restoreAll() will close all tracked clients, preventing timer leaks
  * even if the test throws before reaching its own cleanup code.
  */
-function trackClient(client: any): void {
+function trackClient(client: DefaultRest | DefaultRealtime): void {
   _trackedClients.push(client);
 }
 
@@ -213,9 +217,9 @@ function restoreAll(): void {
   // Close all tracked clients first (before restoring mocks/timers)
   // so their internal timers are cancelled while mocks are still in place.
   while (_trackedClients.length > 0) {
-    const client = _trackedClients.pop();
+    const client = _trackedClients.pop()!;
     try {
-      if (typeof client.close === 'function') {
+      if (client instanceof DefaultRealtime) {
         client.close();
       }
     } catch (_) {
@@ -227,8 +231,8 @@ function restoreAll(): void {
   // Restore fake timers if installed
   if (_savedSetTimeout) {
     Platform.Config.setTimeout = _savedSetTimeout;
-    Platform.Config.clearTimeout = _savedClearTimeout;
-    Platform.Config.now = _savedNow;
+    Platform.Config.clearTimeout = _savedClearTimeout!;
+    Platform.Config.now = _savedNow!;
     _savedSetTimeout = null;
     _savedClearTimeout = null;
     _savedNow = null;
@@ -237,6 +241,7 @@ function restoreAll(): void {
 
 export {
   Ably,
+  ErrorInfo,
   Platform,
   installMockHttp,
   uninstallMockHttp,

diff --git a/test/uts/mock_http.ts b/test/uts/mock_http.ts
@@ -7,17 +7,20 @@
  * See: specification/uts/rest/unit/helpers/mock_http.md
  */
 
+import {
+  IPlatformHttpStatic,
+  RequestResult,
+  RequestResultError,
+  ErrnoException,
+  RequestBody,
+  RequestParams,
+} from '../../src/common/types/http';
+import HttpMethods from '../../src/common/constants/HttpMethods';
+import ErrorInfo from '../../src/common/lib/types/errorinfo';
+
 interface ConnectionResult {
   success: boolean;
-  error?: { code: string; statusCode: number; message: string };
-}
-
-interface RequestResult {
-  error: { message: string; code: number; statusCode: number } | null;
-  body: string | null;
-  headers: Record<string, string>;
-  unpacked: boolean;
-  statusCode: number;
+  error?: ErrnoException;
 }
 
 /**
@@ -50,17 +53,20 @@ class PendingConnection {
 
   /** Connection refused at network level */
   respond_with_refused(): void {
-    this._resolve!({ success: false, error: { code: 'ECONNREFUSED', statusCode: 500, message: 'Connection refused' } });
+    const err = Object.assign(new Error('Connection refused'), { code: 'ECONNREFUSED', statusCode: 500 }) as ErrnoException;
+    this._resolve!({ success: false, error: err });
   }
 
   /** Connection times out (unresponsive) */
   respond_with_timeout(): void {
-    this._resolve!({ success: false, error: { code: 'ETIMEDOUT', statusCode: 500, message: 'Connection timed out' } });
+    const err = Object.assign(new Error('Connection timed out'), { code: 'ETIMEDOUT', statusCode: 500 }) as ErrnoException;
+    this._resolve!({ success: false, error: err });
   }
 
   /** DNS resolution fails */
   respond_with_dns_error(): void {
-    this._resolve!({ success: false, error: { code: 'ENOTFOUND', statusCode: 500, message: 'DNS resolution failed' } });
+    const err = Object.assign(new Error('DNS resolution failed'), { code: 'ENOTFOUND', statusCode: 500 }) as ErrnoException;
+    this._resolve!({ success: false, error: err });
   }
 }
 
@@ -73,7 +79,7 @@ class PendingRequest {
   url: URL;
   path: string;
   headers: Record<string, string>;
-  body: any;
+  body: string | null; // always a text representation; Buffer/ArrayBuffer bodies are toString'd by the mock
   params: Record<string, string> | null;
   timestamp: number;
   _resolve: ((value: RequestResult) => void) | null;
@@ -83,14 +89,14 @@ class PendingRequest {
     method: string,
     uri: string,
     headers?: Record<string, string>,
-    body?: any,
+    body?: RequestBody | null,
     params?: Record<string, string> | null,
   ) {
     this.method = method;
     this.url = new URL(uri);
     this.path = this.url.pathname;
     this.headers = headers || {};
-    this.body = body;
+    this.body = body == null ? null : typeof body === 'string' ? body : body.toString();
     this.params = params || null;
     this.timestamp = Date.now();
     this._resolve = null;
@@ -100,19 +106,20 @@ class PendingRequest {
   }
 
   /** Respond with an HTTP response */
-  respond_with(status: number, body: any, headers?: Record<string, string>): void {
+  respond_with(status: number, body: unknown, headers?: Record<string, string>): void {
     const responseHeaders = headers || {};
     const isError = status >= 400;
     let error: RequestResult['error'] = null;
 
     if (isError) {
       // Extract error info from body if present
-      const errBody = typeof body === 'object' && body !== null && body.error ? body.error : null;
-      error = {
-        message: errBody ? errBody.message : `HTTP ${status}`,
-        code: errBody ? errBody.code : status * 100,
-        statusCode: errBody ? errBody.statusCode || status : status,
-      };
+      const bodyObj = typeof body === 'object' && body !== null ? (body as Record<string, unknown>) : null;
+      const errBody = (bodyObj?.error as { message?: string; code?: number; statusCode?: number } | null) ?? null;
+      error = new ErrorInfo(
+        errBody?.message ?? `HTTP ${status}`,
+        errBody?.code ?? status * 100,
+        errBody?.statusCode ?? status,
+      );
     }
 
     this._resolve!({
@@ -126,8 +133,10 @@ class PendingRequest {
 
   /** Request times out after connection established */
   respond_with_timeout(): void {
+    // code '408' (non-POSIX string) keeps shouldFallback() returning false
+    const err = Object.assign(new Error('Request timed out'), { code: '408', statusCode: 408 }) as ErrnoException;
     this._resolve!({
-      error: { code: 408, statusCode: 408, message: 'Request timed out' } as any,
+      error: err,
       body: null,
       headers: {},
       unpacked: false,
@@ -212,13 +221,13 @@ class MockHttpClient {
    * Returns an object conforming to IPlatformHttpStatic that can be assigned
    * to Platform.Http.
    */
-  asPlatformHttp(): any {
+  asPlatformHttp(): IPlatformHttpStatic {
     const mock = this;
 
     class MockPlatformHttp {
-      static methods = ['get', 'delete', 'post', 'put', 'patch'];
-      static methodsWithBody = ['post', 'put', 'patch'];
-      static methodsWithoutBody = ['get', 'delete'];
+      static methods: HttpMethods[] = [HttpMethods.Get, HttpMethods.Delete, HttpMethods.Post, HttpMethods.Put, HttpMethods.Patch];
+      static methodsWithBody: HttpMethods[] = [HttpMethods.Post, HttpMethods.Put, HttpMethods.Patch];
+      static methodsWithoutBody: HttpMethods[] = [HttpMethods.Get, HttpMethods.Delete];
 
       supportsAuthHeaders: boolean;
       supportsLinkHeaders: boolean;
@@ -229,11 +238,11 @@ class MockHttpClient {
       }
 
       async doUri(
-        method: string,
+        method: HttpMethods,
         uri: string,
-        headers: Record<string, string>,
-        body: any,
-        params: Record<string, string>,
+        headers: Record<string, string> | null,
+        body: RequestBody | null,
+        params: RequestParams,
       ): Promise<RequestResult> {
         // Phase 1: Connection attempt
         let parsedUrl: URL;
@@ -252,7 +261,7 @@ class MockHttpClient {
           parsedUrl = new URL(fullUri);
         } catch (e) {
           return {
-            error: { message: 'Invalid URI: ' + uri, statusCode: 400, code: 40000 },
+            error: new ErrorInfo('Invalid URI: ' + uri, 40000, 400),
             body: null,
             headers: {},
             unpacked: false,
@@ -279,11 +288,11 @@ class MockHttpClient {
         const connResult = await conn._promise;
 
         if (!connResult.success) {
-          return { error: connResult.error as any, body: null, headers: {}, unpacked: false, statusCode: 0 };
+          return { error: connResult.error ?? null, body: null, headers: {}, unpacked: false, statusCode: 0 };
         }
 
         // Phase 2: HTTP request (use parsedUrl which includes params)
-        const req = new PendingRequest(method, parsedUrl.href, headers, body, params);
+        const req = new PendingRequest(method, parsedUrl.href, headers ?? undefined, body, params);
         mock.captured_requests.push(req);
 
         // Notify handler or waiter
@@ -302,13 +311,13 @@ class MockHttpClient {
       async checkConnectivity(): Promise<boolean> {
         // Perform the connectivity check via doUri (same as real implementation)
         const url = 'https://internet-up.ably-realtime.com/is-the-internet-up.txt';
-        const { error, body } = await this.doUri('get', url, {}, null, null as any);
+        const { error, body } = await this.doUri(HttpMethods.Get, url, {}, null, null);
         return !error && (body as string)?.toString().trim() === 'yes';
       }
 
-      shouldFallback(error: any): boolean {
+      shouldFallback(error: RequestResultError): boolean {
         if (!error) return false;
-        const code = error.code;
+        const code = (error as ErrnoException).code;
         const statusCode = error.statusCode;
         if (
           code === 'ECONNREFUSED' ||
@@ -320,11 +329,11 @@ class MockHttpClient {
         ) {
           return true;
         }
-        return statusCode >= 500 && statusCode <= 504;
+        return (statusCode ?? 0) >= 500 && (statusCode ?? 0) <= 504;
       }
     }
 
-    return MockPlatformHttp;
+    return MockPlatformHttp as unknown as IPlatformHttpStatic;
   }
 }
 

diff --git a/test/uts/realtime/time.test.ts b/test/uts/realtime/time.test.ts
@@ -10,8 +10,8 @@
  */
 
 import { expect } from 'chai';
-import { MockHttpClient } from '../mock_http';
-import { Ably, installMockHttp, restoreAll } from '../helpers';
+import { MockHttpClient, PendingRequest } from '../mock_http';
+import { Ably, ErrorInfo, installMockHttp, restoreAll } from '../helpers';
 
 describe('uts/realtime/time', function () {
   let mock;
@@ -24,7 +24,7 @@ describe('uts/realtime/time', function () {
    * RTC6a - time() returns server time (proxied from REST)
    */
   it('RTC6a - time() returns server time', async function () {
-    const captured: any[] = [];
+    const captured: PendingRequest[] = [];
     const serverTimeMs = 1704067200000;
 
     mock = new MockHttpClient({
@@ -51,7 +51,7 @@ describe('uts/realtime/time', function () {
    * RTC6a - time() request format (proxied from REST)
    */
   it('RTC6a - time() request format', async function () {
-    const captured: any[] = [];
+    const captured: PendingRequest[] = [];
 
     mock = new MockHttpClient({
       onConnectionAttempt: (conn) => conn.respond_with_success(),
@@ -80,7 +80,7 @@ describe('uts/realtime/time', function () {
    * RTC6a - time() does not require authentication (proxied from REST)
    */
   it('RTC6a - time() does not require authentication', async function () {
-    const captured: any[] = [];
+    const captured: PendingRequest[] = [];
 
     mock = new MockHttpClient({
       onConnectionAttempt: (conn) => conn.respond_with_success(),
@@ -104,7 +104,7 @@ describe('uts/realtime/time', function () {
    * RTC6a - time() works without TLS (proxied from REST)
    */
   it('RTC6a - time() works without TLS', async function () {
-    const captured: any[] = [];
+    const captured: PendingRequest[] = [];
 
     mock = new MockHttpClient({
       onConnectionAttempt: (conn) => conn.respond_with_success(),
@@ -153,9 +153,9 @@ describe('uts/realtime/time', function () {
     try {
       await client.time();
       expect.fail('Expected time() to throw');
-    } catch (error: any) {
-      expect(error.statusCode).to.equal(500);
-      expect(error.code).to.equal(50000);
+    } catch (error) {
+      expect((error as ErrorInfo).statusCode).to.equal(500);
+      expect((error as ErrorInfo).code).to.equal(50000);
     }
   });
 });