Revert "Upgrade @playwright/test and cleanup internal APIs" (#77814)

Reverts #77659


[x-ref](https://vercel.slack.com/archives/C03KAR5DCKC/p1743745064109939?thread_ts=1743528456.364379&cid=C03KAR5DCKC)

Author: huozhi

packages/next/package.json

@@ -110,7 +110,7 @@
   },
   "peerDependencies": {
     "@opentelemetry/api": "^1.1.0",
-    "@playwright/test": "^1.51.1",
+    "@playwright/test": "^1.41.2",
     "babel-plugin-react-compiler": "*",
     "react": "^18.2.0 || 19.0.0-rc-de68d2f4-20241204 || ^19.0.0",
     "react-dom": "^18.2.0 || 19.0.0-rc-de68d2f4-20241204 || ^19.0.0",
@@ -170,7 +170,7 @@
     "@next/react-refresh-utils": "15.3.0-canary.34",
     "@next/swc": "15.3.0-canary.34",
     "@opentelemetry/api": "1.6.0",
-    "@playwright/test": "1.51.1",
+    "@playwright/test": "1.41.2",
     "@storybook/addon-a11y": "8.6.0",
     "@storybook/addon-essentials": "8.6.0",
     "@storybook/addon-interactions": "8.6.0",

packages/next/src/experimental/testmode/playwright/step.ts

@@ -9,13 +9,33 @@ export interface StepProps {
   params?: Record<string, string | number | boolean | null | undefined>
 }
 
+// Access the internal Playwright API until it's exposed publicly.
+// See https://github.com/microsoft/playwright/issues/27059.
+interface TestInfoWithRunAsStep extends TestInfo {
+  _runAsStep: <T>(
+    stepInfo: StepProps,
+    handler: (result: { complete: Complete }) => Promise<T>
+  ) => Promise<T>
+}
+
 type Complete = (result: { error?: any }) => void
 
+function isWithRunAsStep(
+  testInfo: TestInfo
+): testInfo is TestInfoWithRunAsStep {
+  return '_runAsStep' in testInfo
+}
+
 export async function step<T>(
-  _testInfo: TestInfo,
+  testInfo: TestInfo,
   props: StepProps,
   handler: (complete: Complete) => Promise<Awaited<T>>
 ): Promise<Awaited<T>> {
+  if (isWithRunAsStep(testInfo)) {
+    return testInfo._runAsStep(props, ({ complete }) => handler(complete))
+  }
+
+  // Fallback to the `test.step()`.
   let result: Awaited<T>
   let reportedError: any
   try {