From c0704b2b816b1e585bc14d5cfb7e8f44e9c46fd6 Mon Sep 17 00:00:00 2001
From: Michael Carpenter <mcarpenter@twilio.com>
Date: Thu, 9 Apr 2026 16:23:29 -0700
Subject: [PATCH] feat(@twilio/runtime-handler): export Response class for
 testing

Export the Response class from the package root, enabling unit testing of
Twilio Functions without custom mock implementations.

Previously, the main entry point was a placeholder that threw on import.
Now require('@twilio/runtime-handler') returns { Response }, providing
the same class used by the local dev server with full method support
(setStatusCode, setBody, appendHeader, setCookie, etc).

Closes #384
---
 .changeset/export-response-class.md                |  5 +++++
 .../__tests__/runtime-handler.test.ts              | 14 ++++++++++----
 packages/runtime-handler/package.json              |  9 +++++----
 packages/runtime-handler/src/index.ts              |  2 +-
 4 files changed, 21 insertions(+), 9 deletions(-)
 create mode 100644 .changeset/export-response-class.md

diff --git a/.changeset/export-response-class.md b/.changeset/export-response-class.md
new file mode 100644
index 00000000..604b6c29
--- /dev/null
+++ b/.changeset/export-response-class.md
@@ -0,0 +1,5 @@
+---
+"@twilio/runtime-handler": minor
+---
+
+Export Response class from the package root for use in testing. Previously, the package's main entry was a placeholder that threw on import. Now `const { Response } = require('@twilio/runtime-handler')` provides the same Response class used by the local dev runtime, enabling proper unit testing of Twilio Functions without custom mocks.
diff --git a/packages/runtime-handler/__tests__/runtime-handler.test.ts b/packages/runtime-handler/__tests__/runtime-handler.test.ts
index 629907f5..e544e1f1 100644
--- a/packages/runtime-handler/__tests__/runtime-handler.test.ts
+++ b/packages/runtime-handler/__tests__/runtime-handler.test.ts
@@ -1,5 +1,11 @@
-test('base should not be importable', () => {
-  expect(() => {
-    require('..');
-  }).toThrow();
+test('base export includes Response class', () => {
+  const { Response } = require('..');
+  expect(Response).toBeDefined();
+  expect(typeof Response).toBe('function');
+
+  const res = new Response();
+  expect(res.setStatusCode).toBeDefined();
+  expect(res.setBody).toBeDefined();
+  expect(res.appendHeader).toBeDefined();
+  expect(res.setCookie).toBeDefined();
 });
diff --git a/packages/runtime-handler/package.json b/packages/runtime-handler/package.json
index ba9a62d0..3abad227 100644
--- a/packages/runtime-handler/package.json
+++ b/packages/runtime-handler/package.json
@@ -9,11 +9,12 @@
   "author": "Twilio Inc. <open-source@twilio.com> (https://www.twilio.com/labs)",
   "homepage": "https://github.com/twilio-labs/serverless-toolkit/tree/main/packages/runtime-handler#readme",
   "license": "MIT",
-  "main": "dist/invalid.js",
-  "types": "dist/invalid.d.ts",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
   "exports": {
-    ".": "./dist/invalid.js",
-    "./dev": "./dist/dev-runtime/dev-runtime.js"
+    ".": "./dist/index.js",
+    "./dev": "./dist/dev-runtime/dev-runtime.js",
+    "./testing": "./dist/index.js"
   },
   "directories": {
     "src": "src",
diff --git a/packages/runtime-handler/src/index.ts b/packages/runtime-handler/src/index.ts
index ff7bd09c..2d250c54 100644
--- a/packages/runtime-handler/src/index.ts
+++ b/packages/runtime-handler/src/index.ts
@@ -1 +1 @@
-// placeholder
+export { Response } from './dev-runtime/internal/response';