fix: add option ignoreTrailingSlash to MockAgent and .intercept()

lib/mock/mock-client.js

@@ -10,7 +10,8 @@ const {
   kOriginalClose,
   kOrigin,
   kOriginalDispatch,
-  kConnected
+  kConnected,
+  kIgnoreTrailingSlash
 } = require('./mock-symbols')
 const { MockInterceptor } = require('./mock-interceptor')
 const Symbols = require('../core/symbols')
@@ -29,6 +30,7 @@ class MockClient extends Client {
 
     this[kMockAgent] = opts.agent
     this[kOrigin] = origin
+    this[kIgnoreTrailingSlash] = opts.ignoreTrailingSlash ?? false
     this[kDispatches] = []
     this[kConnected] = 1
     this[kOriginalDispatch] = this.dispatch
@@ -46,7 +48,10 @@ class MockClient extends Client {
    * Sets up the base interceptor for mocking replies from undici.
    */
   intercept (opts) {
-    return new MockInterceptor(opts, this[kDispatches])
+    return new MockInterceptor(
+      opts && { ignoreTrailingSlash: this[kIgnoreTrailingSlash], ...opts },
+      this[kDispatches]
+    )
   }
 
   async [kClose] () {

lib/mock/mock-pool.js

@@ -10,7 +10,8 @@ const {
   kOriginalClose,
   kOrigin,
   kOriginalDispatch,
-  kConnected
+  kConnected,
+  kIgnoreTrailingSlash
 } = require('./mock-symbols')
 const { MockInterceptor } = require('./mock-interceptor')
 const Symbols = require('../core/symbols')
@@ -29,6 +30,7 @@ class MockPool extends Pool {
 
     this[kMockAgent] = opts.agent
     this[kOrigin] = origin
+    this[kIgnoreTrailingSlash] = opts.ignoreTrailingSlash ?? false
     this[kDispatches] = []
     this[kConnected] = 1
     this[kOriginalDispatch] = this.dispatch
@@ -46,7 +48,10 @@ class MockPool extends Pool {
    * Sets up the base interceptor for mocking replies from undici.
    */
   intercept (opts) {
-    return new MockInterceptor(opts, this[kDispatches])
+    return new MockInterceptor(
+      opts && { ignoreTrailingSlash: this[kIgnoreTrailingSlash], ...opts },
+      this[kDispatches]
+    )
   }
 
   async [kClose] () {

lib/mock/mock-symbols.js

@@ -20,5 +20,6 @@ module.exports = {
   kIsMockActive: Symbol('is mock active'),
   kNetConnect: Symbol('net connect'),
   kGetNetConnect: Symbol('get net connect'),
-  kConnected: Symbol('connected')
+  kConnected: Symbol('connected'),
+  kIgnoreTrailingSlash: Symbol('ignore trailing slash')
 }

lib/mock/mock-utils.js

@@ -6,7 +6,8 @@ const {
   kMockAgent,
   kOriginalDispatch,
   kOrigin,
-  kGetNetConnect
+  kGetNetConnect,
+  kIgnoreTrailingSlash
 } = require('./mock-symbols')
 const { serializePathWithQuery } = require('../core/util')
 const { STATUS_CODES } = require('node:http')
@@ -182,7 +183,19 @@ function deleteMockDispatch (mockDispatches, key) {
 }
 
 function buildKey (opts) {
-  const { path, method, body, headers, query } = opts
+  let { path, method, body, headers, query, ignoreTrailingSlash = false } = opts
+
+  // normalize path if it is a string
+  if (ignoreTrailingSlash && typeof path === 'string') {
+    while (path.endsWith('/')) {
+      path = path.slice(0, -1)
+    }
+
+    if (path.length === 0) {
+      path = '/'
+    }
+  }
+
   return {
     path,
     method,
@@ -231,7 +244,7 @@ async function getResponse (body) {
  */
 function mockDispatch (opts, handler) {
   // Get mock dispatch from built key
-  const key = buildKey(opts)
+  const key = buildKey({ ignoreTrailingSlash: this[kIgnoreTrailingSlash], ...opts })
   const mockDispatch = getMockDispatch(this[kDispatches], key)
 
   mockDispatch.timesInvoked++

test/mock-interceptor.js

@@ -259,6 +259,48 @@ describe('MockInterceptor - replyContentLength', () => {
   })
 })
 
+describe('https://github.com/nodejs/undici/issues/3649', () => {
+  [
+    ['/api/some-path', '/api/some-path'],
+    ['/api/some-path/', '/api/some-path'],
+    ['/api/some-path', '/api/some-path/'],
+    ['/api/some-path/', '/api/some-path/'],
+    ['/api/some-path////', '/api/some-path//'],
+    ['', ''],
+    ['/', ''],
+    ['', '/'],
+    ['/', '/']
+  ].forEach(([interceptPath, fetchedPath], index) => {
+    test(`MockAgent should match with or without trailing slash by setting ignoreTrailingSlash as MockAgent option /${index}`, async (t) => {
+      t = tspl(t, { plan: 1 })
+
+      const mockAgent = new MockAgent({ ignoreTrailingSlash: true })
+      mockAgent.disableNetConnect()
+      mockAgent
+        .get('https://localhost')
+        .intercept({ path: interceptPath }).reply(200, { ok: true })
+
+      const res = await fetch(new URL(fetchedPath, 'https://localhost'), { dispatcher: mockAgent })
+
+      t.deepStrictEqual(await res.json(), { ok: true })
+    })
+  })
+
+  test('MockAgent should match with or without trailing slash /6', async (t) => {
+    t = tspl(t, { plan: 1 })
+
+    const mockAgent = new MockAgent()
+    mockAgent.disableNetConnect()
+    mockAgent
+      .get('https://localhost')
+      .intercept({ path: '/' }).reply(200, { ok: true })
+
+    const res = await fetch(new URL('', 'https://localhost'), { dispatcher: mockAgent })
+
+    t.deepStrictEqual(await res.json(), { ok: true })
+  })
+})
+
 describe('MockInterceptor - different payloads', () => {
   [
     // Buffer

types/mock-agent.d.ts

@@ -46,5 +46,8 @@ declare namespace MockAgent {
   export interface Options extends Agent.Options {
     /** A custom agent to be encapsulated by the MockAgent. */
     agent?: Dispatcher;
+
+    /** Ignore trailing slashes in the path */
+    ignoreTrailingSlash?: boolean;
   }
 }