feat: add unit test for auth client

Author: bywang56

server/aws-lsp-codewhisperer/src/language-server/agenticChat/tools/mcp/mcpManager.ts

@@ -331,7 +331,7 @@ export class McpManager {
                     // streamable http/SSE transport
                     const base = new URL(cfg.url!)
                     try {
-                        // Use HEAD to check if it nees OAuth
+                        // Use HEAD to check if it needs OAuth
                         let headers: Record<string, string> = { ...(cfg.headers ?? {}) }
                         let needsOAuth = false
                         try {

server/aws-lsp-codewhisperer/src/language-server/agenticChat/tools/mcp/mcpOauthClient.test.ts

@@ -0,0 +1,118 @@
+/*!
+ * Copyright Amazon.com, Inc. or its affiliates.
+ * All Rights Reserved. SPDX-License-Identifier: Apache-2.0
+ */
+
+import { expect } from 'chai'
+import * as sinon from 'sinon'
+import * as crypto from 'crypto'
+import * as http from 'http'
+import * as path from 'path'
+import { OAuthClient } from './mcpOauthClient'
+
+const fakeLogger = {
+    log: () => {},
+    debug: () => {},
+    info: () => {},
+    warn: () => {},
+    error: () => {},
+}
+
+const fakeWorkspace = {
+    fs: {
+        exists: async (_path: string) => false,
+        readFile: async (_path: string) => Buffer.from('{}'),
+        writeFile: async (_path: string, _d: any) => {},
+        mkdir: async (_dir: string, _opts: any) => {},
+    },
+} as any
+
+function stubFileSystem(tokenObj?: any, regObj?: any): void {
+    const cacheDir = (OAuthClient as any).cacheDir as string
+    const tokPath = path.join(cacheDir, 'testkey.token.json')
+    const regPath = path.join(cacheDir, 'testkey.registration.json')
+
+    const existsStub = sinon.stub(fakeWorkspace.fs, 'exists')
+    existsStub.callsFake(async (p: any) => {
+        if (p === tokPath && tokenObj) return true
+        if (p === regPath && regObj) return true
+        return false
+    })
+
+    const readStub = sinon.stub(fakeWorkspace.fs, 'readFile')
+    readStub.callsFake(async (p: any) => {
+        if (p === tokPath && tokenObj) return Buffer.from(JSON.stringify(tokenObj))
+        if (p === regPath && regObj) return Buffer.from(JSON.stringify(regObj))
+        return Buffer.from('{}')
+    })
+
+    sinon.stub(fakeWorkspace.fs, 'writeFile').resolves()
+    sinon.stub(fakeWorkspace.fs, 'mkdir').resolves()
+}
+
+function stubHttpServer(): void {
+    sinon.stub(http, 'createServer').returns({
+        listen: (...args: any[]) => {
+            const cb = args.find(a => typeof a === 'function')
+            if (cb) cb()
+            return {} as any
+        },
+        close: (cb?: any) => {
+            if (cb) cb()
+            return {} as any
+        },
+        on: (..._args: any[]) => {
+            return {} as any
+        },
+        address: () => ({ address: '127.0.0.1', port: 12345, family: 'IPv4' }),
+    } as unknown as http.Server)
+}
+
+describe('OAuthClient helpers', () => {
+    it('computeKey() generates deterministic SHA-256 hex', () => {
+        const url = new URL('https://example.com/api')
+        const expected = crypto
+            .createHash('sha256')
+            .update(url.origin + url.pathname)
+            .digest('hex')
+        const actual = (OAuthClient as any).computeKey(url)
+        expect(actual).to.equal(expected)
+    })
+
+    it('b64url() strips padding and is URL-safe', () => {
+        const buf = Buffer.from('hello')
+        const actual = (OAuthClient as any).b64url(buf)
+        expect(actual).to.equal('aGVsbG8')
+    })
+})
+
+describe('OAuthClient getValidAccessToken()', () => {
+    const now = Date.now()
+
+    beforeEach(() => {
+        sinon.restore()
+        OAuthClient.initialize(fakeWorkspace, fakeLogger as any)
+        sinon.stub(OAuthClient as any, 'computeKey').returns('testkey')
+        stubHttpServer()
+    })
+
+    afterEach(() => sinon.restore())
+
+    it('returns cached token when still valid', async () => {
+        const cachedToken = {
+            access_token: 'cached_access',
+            expires_in: 3600,
+            obtained_at: now - 1_000,
+        }
+        const cachedReg = {
+            client_id: 'cid',
+            redirect_uri: 'http://localhost:12345',
+        }
+
+        stubFileSystem(cachedToken, cachedReg)
+
+        const token = await OAuthClient.getValidAccessToken(new URL('https://api.example.com/mcp'))
+        expect(token).to.equal('cached_access')
+        expect((http.createServer as any).calledOnce).to.be.true
+    })
+})