feat(plugins): add expose plugin for direct helper-internals injection

Exposes Playwright/Puppeteer/WebDriver helper properties (page, browser,
browserContext, wdio client) as scenario arguments via a live proxy.
Reads helper.[property] on every access so mid-test reassignment from
switchToNextTab/openNewTab is reflected automatically. Bypasses MetaStep
wrapping so calls run as native SDK calls.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: DavertMik

docs/advanced.md

@@ -154,3 +154,48 @@ You can use this options for build your own [plugins](https://codecept.io/hooks/
     ...
   });
 ```
+
+## Direct Helper Access
+
+Some scenarios need the underlying SDK directly — a raw `page.evaluate`, a `page.on('request')` listener, an experimental Playwright API, or a wdio command the `WebDriver` helper doesn't expose. The `expose` plugin injects helper internals as scenario arguments so you can call them inline.
+
+```js
+Scenario('intercept network', async ({ I, page }) => {
+  page.on('request', req => console.log(req.method(), req.url()))
+  I.amOnPage('/')
+  const title = await page.evaluate(() => document.title)
+  I.see(title)
+})
+```
+Enable `expose` plugin in config and use public properties from a corresponding helper.
+Map each injection name to `HelperName.propertyName`:
+
+```js
+plugins: {
+  expose: {
+    enabled: true,
+    inject: {
+      page: 'Playwright.page',
+      browser: 'Playwright.browser',
+      browserContext: 'Playwright.browserContext',
+      wdio: 'WebDriver.browser',
+    }
+  }
+}
+```
+
+There is a shorthand mode:
+
+```js
+plugins: {
+  expose: {
+    enabled: true,
+    inject: { page: 'page' }   // resolves Playwright.page or Puppeteer.page
+  }
+}
+```
+A value with no dot is shorthand for "the first configured browser helper that exposes this property". Allowed properties: `page`, `browser`, `browserContext`, `context`.
+
+The injected value is a live proxy. Every property access reads the current helper property at that moment, so tab switches (`I.openNewTab`, `I.switchToNextTab`) propagate automatically — the next call through `page` targets the new tab.
+
+Calls pass straight to the underlying SDK. They aren't wrapped as CodeceptJS steps and don't appear in step output, so `await page.evaluate(...)` behaves as native Playwright.

lib/plugin/expose.js

@@ -0,0 +1,159 @@
+import Container from '../container.js'
+
+const RESERVED_NAMES = new Set(['I', 'test', 'suite'])
+const SHORTHAND_PROPERTIES = new Set(['page', 'browser', 'browserContext', 'context'])
+
+const defaultConfig = {
+  inject: {},
+}
+
+/**
+ * Exposes properties from helper instances as injectable test arguments.
+ * Use it to access the underlying Playwright/Puppeteer `page`, the wdio `browser` client,
+ * or any other helper internal directly from a Scenario:
+ *
+ * ```js
+ * Scenario('listen for requests', async ({ I, page, browser }) => {
+ *   page.on('request', r => console.log(r.url()))
+ *   await page.evaluate(() => 1 + 1)
+ *   I.amOnPage('/')
+ * })
+ * ```
+ *
+ * The injected value is a live proxy: every property access reads the *current*
+ * helper property, so mid-test reassignments (popups, `switchToNextTab`,
+ * `openNewTab`) are reflected automatically. Calls are not wrapped as
+ * CodeceptJS steps — `await page.evaluate(...)` runs as native Playwright.
+ *
+ * #### Configuration
+ *
+ * `inject` maps an injection name to a `HelperName.propertyName` string. A
+ * value with no dot is shorthand for "first configured browser helper that
+ * exposes this property" (allowed properties: `page`, `browser`,
+ * `browserContext`, `context`).
+ *
+ * ```js
+ * plugins: {
+ *   expose: {
+ *     enabled: true,
+ *     inject: {
+ *       page: 'Playwright.page',
+ *       browser: 'Playwright.browser',
+ *       browserContext: 'Playwright.browserContext',
+ *       frame: 'Playwright.context',  // current frame set by switchTo
+ *       wdio: 'WebDriver.browser',
+ *     }
+ *   }
+ * }
+ * ```
+ *
+ * Shorthand:
+ *
+ * ```js
+ * plugins: {
+ *   expose: {
+ *     enabled: true,
+ *     inject: {
+ *       page: 'page',  // resolves to Playwright.page or Puppeteer.page
+ *     }
+ *   }
+ * }
+ * ```
+ *
+ * #### Caveats
+ *
+ * - The injected value is a `Proxy`, not the actual `Page`/`Browser` instance,
+ *   so `page instanceof Page` is `false`. Use duck typing instead.
+ * - Cached method references lose the live binding. Call `page.click(...)`,
+ *   not `const click = page.click; click(...)`.
+ * - In dry-run mode the underlying helper property is `undefined`; accessing
+ *   any property on the proxy returns `undefined` rather than throwing.
+ */
+export default function (config = {}) {
+  config = { ...defaultConfig, ...config }
+
+  const mappings = parseMappings(config.inject)
+
+  const support = {}
+  for (const [name, { helperName, property }] of Object.entries(mappings)) {
+    support[name] = makeLiveProxy(helperName, property)
+  }
+  Container.append({ support })
+}
+
+function parseMappings(inject) {
+  const out = {}
+  for (const [name, value] of Object.entries(inject || {})) {
+    if (RESERVED_NAMES.has(name)) {
+      throw new Error(`expose plugin: inject name '${name}' is reserved`)
+    }
+    if (typeof value !== 'string' || !value) {
+      throw new Error(`expose plugin: inject value for '${name}' must be a non-empty string`)
+    }
+
+    let helperName
+    let property
+
+    if (value.includes('.')) {
+      const dot = value.indexOf('.')
+      helperName = value.slice(0, dot)
+      property = value.slice(dot + 1)
+      if (!helperName || !property) {
+        throw new Error(`expose plugin: invalid inject value '${value}' for '${name}' (expected 'HelperName.propertyName')`)
+      }
+      if (!Container.helpers(helperName)) {
+        throw new Error(`expose plugin: helper '${helperName}' is not configured (needed for inject '${name}')`)
+      }
+    } else {
+      property = value
+      if (!SHORTHAND_PROPERTIES.has(property)) {
+        throw new Error(`expose plugin: shorthand '${property}' is not a known helper property for '${name}' (use 'HelperName.${property}' instead)`)
+      }
+      helperName = Container.STANDARD_ACTING_HELPERS.find(h => Container.helpers(h))
+      if (!helperName) {
+        throw new Error(`expose plugin: no standard browser helper configured (needed for inject '${name}')`)
+      }
+    }
+
+    out[name] = { helperName, property }
+  }
+  return out
+}
+
+function makeLiveProxy(helperName, property) {
+  const resolve = () => Container.helpers(helperName)?.[property]
+  return new Proxy(function () {}, {
+    get(_, prop) {
+      const target = resolve()
+      if (target == null) return undefined
+      const value = target[prop]
+      if (typeof value === 'function') return value.bind(target)
+      return value
+    },
+    has(_, prop) {
+      const target = resolve()
+      return target != null && prop in target
+    },
+    apply(_, thisArg, args) {
+      const target = resolve()
+      return target?.apply(thisArg, args)
+    },
+    set(_, prop, value) {
+      const target = resolve()
+      if (target != null) target[prop] = value
+      return true
+    },
+    getPrototypeOf() {
+      const target = resolve()
+      return target != null ? Object.getPrototypeOf(target) : null
+    },
+    ownKeys() {
+      const target = resolve()
+      return target != null ? Reflect.ownKeys(target) : []
+    },
+    getOwnPropertyDescriptor(_, prop) {
+      const target = resolve()
+      return target != null ? Object.getOwnPropertyDescriptor(target, prop) : undefined
+    },
+  })
+}

test/unit/plugin/expose_test.js

@@ -0,0 +1,115 @@
+import { expect } from 'chai'
+import Container from '../../../lib/container.js'
+import expose from '../../../lib/plugin/expose.js'
+
+async function setup(helpers) {
+  await Container.create({ helpers: {} })
+  Object.assign(Container.helpers(), helpers)
+}
+
+describe('expose plugin', () => {
+  afterEach(async () => {
+    await Container.clear()
+  })
+
+  describe('registration', () => {
+    it('registers each inject name as a function-typed support entry', async () => {
+      await setup({ Playwright: { page: null, browser: null } })
+      expose({ inject: { page: 'Playwright.page', browser: 'Playwright.browser' } })
+      expect(typeof Container.support('page')).to.equal('function')
+      expect(typeof Container.support('browser')).to.equal('function')
+    })
+
+    it('makes the injected proxy resolve to the helper property when present', async () => {
+      const fakePage = { url: () => 'http://example.com' }
+      await setup({ Playwright: { page: fakePage } })
+      expose({ inject: { page: 'Playwright.page' } })
+      const page = Container.support('page')
+      expect(page.url()).to.equal('http://example.com')
+    })
+  })
+
+  describe('live proxy', () => {
+    it('reflects mid-test reassignment of helper.page (tab switch)', async () => {
+      const helper = { page: { url: () => 'http://first.com' } }
+      await setup({ Playwright: helper })
+      expose({ inject: { page: 'Playwright.page' } })
+      const page = Container.support('page')
+      expect(page.url()).to.equal('http://first.com')
+      helper.page = { url: () => 'http://second.com' }
+      expect(page.url()).to.equal('http://second.com')
+    })
+
+    it('returns undefined for any property when helper.page is null (post-cleanup, dry-run)', async () => {
+      await setup({ Playwright: { page: null } })
+      expose({ inject: { page: 'Playwright.page' } })
+      const page = Container.support('page')
+      expect(page.click).to.equal(undefined)
+      expect(page.evaluate).to.equal(undefined)
+    })
+
+    it('binds method calls to the current helper.page so `this` resolves correctly', async () => {
+      const helper = {
+        page: {
+          name: 'one',
+          who() { return this.name },
+        },
+      }
+      await setup({ Playwright: helper })
+      expose({ inject: { page: 'Playwright.page' } })
+      const page = Container.support('page')
+      expect(page.who()).to.equal('one')
+      helper.page = { name: 'two', who() { return this.name } }
+      expect(page.who()).to.equal('two')
+    })
+
+    it('does not wrap method results in MetaStep (returns raw values)', async () => {
+      const ctx = { kind: 'BrowserContext' }
+      await setup({ Playwright: { page: { context: () => ctx } } })
+      expose({ inject: { page: 'Playwright.page' } })
+      const page = Container.support('page')
+      expect(page.context()).to.equal(ctx)
+    })
+  })
+
+  describe('shorthand', () => {
+    it('resolves to the first configured standard browser helper', async () => {
+      const fakePage = { mark: 'puppeteer' }
+      await setup({ Puppeteer: { page: fakePage } })
+      expose({ inject: { page: 'page' } })
+      expect(Container.support('page').mark).to.equal('puppeteer')
+    })
+
+    it('rejects unknown shorthand properties', async () => {
+      await setup({ Playwright: {} })
+      expect(() => expose({ inject: { x: 'unknownProp' } })).to.throw(/shorthand 'unknownProp' is not a known helper property/)
+    })
+  })
+
+  describe('validation', () => {
+    it('throws when injection name is reserved', async () => {
+      await setup({ Playwright: { page: null } })
+      expect(() => expose({ inject: { I: 'Playwright.page' } })).to.throw(/inject name 'I' is reserved/)
+    })
+
+    it('throws when explicit helper is not configured', async () => {
+      await setup({})
+      expect(() => expose({ inject: { page: 'Playwright.page' } })).to.throw(/helper 'Playwright' is not configured/)
+    })
+
+    it('throws when shorthand has no candidate helper', async () => {
+      await setup({})
+      expect(() => expose({ inject: { page: 'page' } })).to.throw(/no standard browser helper configured/)
+    })
+
+    it('throws on malformed value', async () => {
+      await setup({ Playwright: {} })
+      expect(() => expose({ inject: { page: 'Playwright.' } })).to.throw(/invalid inject value/)
+    })
+
+    it('accepts empty inject', async () => {
+      await setup({ Playwright: { page: null } })
+      expect(() => expose({})).not.to.throw()
+    })
+  })
+})