tests: Add E2E Tests for MCP Worker #488

jonathannorris · 2025-08-13T01:54:14Z

This PR introduces comprehensive end-to-end testing infrastructure for the MCP worker using Vitest and Cloudflare Workers testing pool.

Changes

✅ Added E2E test suite covering:
- MCP protocol compliance and handshake
- Tool discovery and listing
- Worker startup and basic functionality
- Authentication requirements
🛠️ Set up Vitest with Cloudflare Workers testing pool
📦 Resolved dependency conflicts by pinning @types/[email protected] to maintain build compatibility
🔧 Added test-specific worker entry point to mock MCP SDK during tests

Testing

yarn test:worker - Run the new E2E tests
yarn build - Verified TypeScript compilation works correctly

Files Added

Test suites: mcpProtocol.test.ts, tools.test.ts, startup.test.ts, minimal.test.ts
Test helpers: Auth mocking, fixtures, and MCP client utilities
Test configuration: vitest.config.ts, wrangler.test.toml

All tests passing ✅

JamieSinn · 2025-08-14T13:50:46Z

mcp-worker/test/helpers/auth.ts

+export function createMockEnv(overrides: Partial<Env> = {}): Env {
+    return {
+        NODE_ENV: 'test',
+        API_BASE_URL: 'https://api-test.devcycle.com',
+        AUTH0_DOMAIN: 'test-auth.devcycle.com',
+        AUTH0_AUDIENCE: 'https://api-test.devcycle.com/',
+        AUTH0_SCOPE: 'openid profile email offline_access',
+        AUTH0_CLIENT_ID: 'test-client-id',
+        AUTH0_CLIENT_SECRET: 'test-client-secret',


shouldn't these be in the fixtures?

kaushalkapasi · 2025-08-14T13:51:14Z

mcp-worker/worker-configuration.d.ts

        [key: string]: any;
    }, options?: DynamicDispatchOptions): Fetcher;
 }
+declare module 'cloudflare:test' {


duplicate definition from mcp-worker/test-types.d.ts?

this file is auto-generated from wrangler, so not sure. Will run the type gen again and see.

…dflare Workers testing pool

- update vitest to ^3.2.4 and @cloudflare/vitest-pool-workers to ^0.8.62 - add @types/[email protected] resolution to fix TypeScript build errors - ensure both yarn test and yarn build work correctly

… patterns

Co-authored-by: Copilot <[email protected]>

Copilot

Pull Request Overview

This PR introduces comprehensive end-to-end testing infrastructure for the MCP worker using Vitest and Cloudflare Workers testing pool.

Sets up E2E test suite covering MCP protocol compliance, tool discovery, and worker startup functionality
Configures Vitest with Cloudflare Workers testing pool for realistic worker environment testing
Creates test-specific worker entry point to avoid AJV compatibility issues during testing

Reviewed Changes

Copilot reviewed 14 out of 17 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
package.json	Updates test scripts to include worker tests and pins @types/estree version
mcp-worker/vitest.config.ts	Configures Vitest with Cloudflare Workers testing pool
mcp-worker/wrangler.test.toml	Test environment configuration for the worker
mcp-worker/tsconfig.json	Updates TypeScript config to include test files and types
mcp-worker/package.json	Adds Vitest and testing dependencies
mcp-worker/src/test-index.ts	Mock worker entry point for testing
mcp-worker/test/setup.ts	Global test setup file
mcp-worker/test/helpers/*	Test utilities for MCP client, fixtures, and auth mocking
mcp-worker/test/e2e/*.test.ts	E2E test suites for protocol compliance and functionality

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

Copilot · 2025-08-14T15:46:18Z

mcp-worker/test/helpers/auth.ts

+
+    // Create a simple base64-encoded mock JWT (not cryptographically valid)
+    const header = btoa(JSON.stringify({ typ: 'JWT', alg: 'HS256' }))
+    const encodedPayload = btoa(JSON.stringify(payload))


The mock JWT creation uses btoa() which is not available in the Cloudflare Workers runtime. Consider using a base64 encoding method compatible with the Workers environment.

Suggested change

const encodedPayload = btoa(JSON.stringify(payload))

const header = base64Encode(JSON.stringify({ typ: 'JWT', alg: 'HS256' }))

const encodedPayload = base64Encode(JSON.stringify(payload))

Copilot · 2025-08-14T15:46:18Z

mcp-worker/test/helpers/auth.ts

+    const mockJWT = createMockJWT(jwtClaims)
+
+    // Parse the claims from the mock JWT
+    const payload = JSON.parse(atob(mockJWT.split('.')[1]))


The atob() function is not available in the Cloudflare Workers runtime. Use a base64 decoding method compatible with the Workers environment instead.

Suggested change

const payload = JSON.parse(atob(mockJWT.split('.')[1]))

const payload = JSON.parse(base64Decode(mockJWT.split('.')[1]))

Copilot · 2025-08-14T15:46:19Z

mcp-worker/test/helpers/fixtures.ts

+    'createDevCycleVariation',
+    'updateDevCycleVariation',
+]
+


The expectedToolNames array is defined but not used in the actual tests. This creates a maintenance burden as it may become outdated. Consider using this list in the test assertions or remove it if not needed.

Suggested change

*

*/

jonathannorris · 2025-08-14T18:19:15Z

These tests need a bunch of working, going to make them draft again

jonathannorris requested a review from a team as a code owner August 13, 2025 01:54

jonathannorris requested a review from Copilot August 13, 2025 01:54

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jonathannorris requested review from JamieSinn, Copilot, jsalaber and kaushalkapasi August 13, 2025 01:58

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JamieSinn reviewed Aug 14, 2025

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kaushalkapasi reviewed Aug 14, 2025

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jonathannorris and others added 10 commits August 14, 2025 11:35

test: add comprehensive E2E tests for mcp-worker with Vitest and Clou…

c281c20

…dflare Workers testing pool

fix: resolve vitest dependency conflicts and build errors

e10b067

- update vitest to ^3.2.4 and @cloudflare/vitest-pool-workers to ^0.8.62 - add @types/[email protected] resolution to fix TypeScript build errors - ensure both yarn test and yarn build work correctly

chore: remove redundant miniflare config from vitest config

394d231

chore: address Copilot feedback - remove console.log and improve test…

bfb3bec

… patterns

chore: remove global console override from test setup

2d6b0a7

chore: improve TypeScript types in MCP protocol tests

ccd12b7

Update mcp-worker/test/e2e/tools.test.ts

37bd677

Co-authored-by: Copilot <[email protected]>

chore: fix TypeScript linter errors and improve type safety

0eb32d8

chore: add missing semicolon in test-types.d.ts

b39690f

test: centralize mock env defaults in fixtures and update createMockEnv

5545341

jonathannorris force-pushed the test-mcp-worker-e2e-cherry-pick branch from dbb33d7 to 5545341 Compare August 14, 2025 15:36

jonathannorris requested a review from Copilot August 14, 2025 15:41

Copilot AI reviewed Aug 14, 2025

View reviewed changes

jonathannorris marked this pull request as draft August 14, 2025 18:19

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	const encodedPayload = btoa(JSON.stringify(payload))
	const header = base64Encode(JSON.stringify({ typ: 'JWT', alg: 'HS256' }))
	const encodedPayload = base64Encode(JSON.stringify(payload))

	const payload = JSON.parse(atob(mockJWT.split('.')[1]))
	const payload = JSON.parse(base64Decode(mockJWT.split('.')[1]))

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jonathannorris commented Aug 13, 2025 •

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