mock: allow absolute deps, not node builtins

Fix: #948

src/mock/src/index.ts

@@ -1,6 +1,7 @@
 import { plugin as AfterPlugin } from '@tapjs/after'
 import { TapPlugin, TestBase } from '@tapjs/core'
 import * as stack from '@tapjs/stack'
+import { isBuiltin } from 'node:module'
 import { mockRequire } from './mock-require.js'
 import { MockService } from './mock-service.js'
 
@@ -23,7 +24,10 @@ export class TapMock {
     TapMock.#refs.set(t, this)
     // inherit #allMock
     const p = t.parent && TapMock.#refs.get(t.parent)
-    this.#allMock = Object.assign(Object.create(null), p ? p.#allMock : {})
+    this.#allMock = Object.assign(
+      Object.create(null),
+      p ? p.#allMock : {}
+    )
   }
 
   /**
@@ -132,7 +136,14 @@ export class TapMock {
    *
    * @group Spies, Mocks, and Fixtures
    */
-  mockImport(module: string, mocks: Record<string, any> = {}) {
+  async mockImport(module: string, mocks: Record<string, any> = {}) {
+    if (isBuiltin(module)) {
+      this.#t.t.currentAssert = this.mockImport
+      this.#t.t.fail(
+        'Node built-in modules cannot have their imports mocked'
+      )
+      return {}
+    }
     mocks = Object.assign({}, this.#allMock, mocks)
     if (!this.#didTeardown && this.#t.t.pluginLoaded(AfterPlugin)) {
       this.#didTeardown = true
@@ -144,7 +155,7 @@ export class TapMock {
       this.#t.t.mockImport
     )
     this.#mocks.push(service)
-    return import(service.module)
+    return Promise.resolve(service.module).then(s => import(s))
   }
 
   /**
@@ -167,6 +178,13 @@ export class TapMock {
    * @group Spies, Mocks, and Fixtures
    */
   mockRequire(module: string, mocks: Record<string, any> = {}) {
+    if (isBuiltin(module)) {
+      this.#t.t.currentAssert = this.mockRequire
+      this.#t.t.fail(
+        'Node built-in modules cannot have their imports mocked'
+      )
+      return {}
+    }
     mocks = Object.assign({}, this.#allMock, mocks)
     return mockRequire(module, mocks, this.#t.t.mockRequire)
   }

src/mock/src/mock-service.ts

@@ -30,6 +30,7 @@ import { pathToFileURL } from 'url'
 import { MessagePort } from 'worker_threads'
 import { exportLine } from './export-line.js'
 import { mungeMocks } from './munge-mocks.js'
+import { resolveMockEntryPoint } from './resolve-mock-entry-point.js'
 import { serviceKey } from './service-key.js'
 
 const { hasOwnProperty } = Object.prototype
@@ -114,7 +115,7 @@ g[kInstances] = instances
 const mockServiceCtorSymbol = Symbol('private')
 export class MockService {
   key: string = getKey()
-  module?: string
+  module?: string | Promise<string>
   mocks?: Record<string, Record<string, any>>
   caller?: {
     path: string
@@ -227,7 +228,7 @@ export class MockService {
     module: string,
     mocks: Record<string, any> = {},
     caller: Function | ((...a: any[]) => any) = MockService.create
-  ): MockService & { module: string } {
+  ): MockService & { module: string | Promise<string> } {
     const ms = new MockService(mockServiceCtorSymbol)
 
     /* c8 ignore start */
@@ -243,13 +244,18 @@ export class MockService {
     if (!path) {
       throw new Error('could not get current call site')
     }
+
     const dir = dirname(path)
     const url = pathToFileURL(path)
-    const mockedModuleURL = new URL(module, url)
-    mockedModuleURL.searchParams.set(
-      'tapmock',
-      `${serviceKey}.${ms.key}`
+
+    const resolved = resolveMockEntryPoint(
+      url,
+      module,
+      serviceKey,
+      ms.key,
+      caller
     )
+    resolved.then(s => (ms.module = s))
 
     ms.mocks = mungeMocks(mocks, dir)
     ms.caller = {
@@ -263,9 +269,7 @@ export class MockService {
     const g = globalThis as typeof globalThis & {
       [sym]?: MockService
     }
-    return (g[sym] = Object.assign(ms, {
-      module: String(mockedModuleURL),
-    }))
+    return (g[sym] = Object.assign(ms, { module: resolved }))
   }
 
   unmock() {

src/mock/src/resolve-mock-entry-point.ts

@@ -0,0 +1,30 @@
+import { resolveImport } from 'resolve-import'
+
+export const resolveMockEntryPoint = async (
+  url: URL,
+  module: string,
+  serviceKey: string,
+  key: string,
+  caller: Function | ((...a: any[]) => any)
+): Promise<string> => {
+  let mockedModuleURL: URL
+  if (module.startsWith('./') || module.startsWith('../')) {
+    mockedModuleURL = new URL(module, url)
+  } else {
+    const res = (await resolveImport(module, url)) as URL
+    // caught at the exposed API, defense in depth only
+    // but the experience if it throws here is unhelpful.
+    /* c8 ignore start */
+    if (typeof res === 'string') {
+      const er = new TypeError(
+        'node builtins cannot be mock imported'
+      )
+      Error.captureStackTrace(er, caller)
+      throw er
+    }
+    /* c8 ignore stop */
+    mockedModuleURL = res
+  }
+  mockedModuleURL.searchParams.set('tapmock', `${serviceKey}.${key}`)
+  return String(mockedModuleURL)
+}

src/mock/test/index.ts

@@ -1,5 +1,5 @@
 import { relative } from 'path'
-import t from 'tap'
+import t, { Test } from 'tap'
 import { loader, plugin } from '../dist/esm/index.js'
 
 const __dirname = fileURLToPath(new URL('.', import.meta.url))
@@ -172,3 +172,29 @@ t.test('mockAll editing', t => {
   t.same(t.mockAll(null), {})
   t.end()
 })
+
+t.test('cannot mock node builtins', async t => {
+  const tt = new Test({ name: 'failing mocker' })
+  tt.runMain(() => {})
+  tt.test('subtest', async t => {
+    await t.mockImport('fs')
+    t.mockRequire('fs')
+  })
+  tt.end()
+  const result = await tt.concat()
+  t.equal(tt.passing(), false)
+  t.match(
+    result,
+    `
+            await t.mockImport('fs')
+        ------------^
+`
+  )
+  t.match(
+    result,
+    `
+            t.mockRequire('fs')
+        ------^
+`
+  )
+})

src/mock/test/mock-service.ts

@@ -132,7 +132,7 @@ t.test('generate some mock imports', async t => {
   )
   const expect = new URL(mod, import.meta.url)
   expect.searchParams.set('tapmock', `${serviceKey}.${service.key}`)
-  t.equal(service.module, String(expect))
+  t.equal(await service.module, String(expect))
   t.type(service.key, 'string')
   t.match(service, {
     mocks: {
@@ -167,7 +167,7 @@ t.test('generate some mock imports', async t => {
       stack: String,
     },
   })
-  t.strictSame(await import(service.module), {
+  t.strictSame(await import(await service.module), {
     __proto__: null,
     foo: 'bar',
     myFS: 'hello from fs',
@@ -242,39 +242,39 @@ t.test('create with no mocks, nothing to resolve', async t => {
     action: 'resolve',
     id: 'whatever',
     url: './blah.mjs',
-    parentURL: service.module,
+    parentURL: await service.module,
   }), String(expect))
 
   t.equal(await MSCJS.resolve({
     action: 'resolve',
     id: 'whatever',
     url: './blah.mjs',
-    parentURL: service.module,
+    parentURL: await service.module,
   }), String(expect))
 
   t.equal(await service.resolve({
     action: 'resolve',
     id: 'whatever',
     url: './blah.mjs',
-    parentURL: service.module,
+    parentURL: await service.module,
   }), String(expect))
 
   t.equal(await service.resolve({
     action: 'resolve',
     id: 'another one',
     url: './nonexistent.mjs',
-    parentURL: service.module,
+    parentURL: await service.module,
   }), undefined)
   t.equal(await MockService.resolve({
     action: 'resolve',
     id: 'another one',
     url: './nonexistent.mjs',
-    parentURL: service.module,
+    parentURL: await service.module,
   }), undefined)
   t.equal(await MSCJS.resolve({
     action: 'resolve',
     id: 'another one',
     url: './nonexistent.mjs',
-    parentURL: service.module,
+    parentURL: await service.module,
   }), undefined)
 })

src/mock/test/resolve-mock-entry-point.ts

@@ -0,0 +1,30 @@
+import { resolveImport } from 'resolve-import'
+import t from 'tap'
+
+import { resolveMockEntryPoint } from '../src/resolve-mock-entry-point.js'
+
+t.equal(
+  await resolveMockEntryPoint(
+    new URL(import.meta.url),
+    '../dist/esm/hooks.mjs',
+    'service-key',
+    'mock-key',
+    () => {}
+  ),
+  String(
+    await resolveImport('../dist/esm/hooks.mjs', import.meta.url)
+  ) + '?tapmock=service-key.mock-key'
+)
+
+t.equal(
+  await resolveMockEntryPoint(
+    new URL(import.meta.url),
+    '@tapjs/synonyms',
+    'service-key',
+    'mock-key',
+    () => {}
+  ),
+  String(
+    await resolveImport('@tapjs/synonyms', import.meta.url)
+  ) + '?tapmock=service-key.mock-key'
+)