test: optimistic form state rows (#12055)

Adds tests for #11961.

test/helpers/e2e/assertElementStaysVisible.ts

@@ -0,0 +1,26 @@
+import type { Page } from 'playwright'
+
+export async function assertElementStaysVisible(
+  page: Page,
+  selector: string,
+  durationMs: number = 3000,
+  pollIntervalMs: number = 250,
+): Promise<void> {
+  const start = Date.now()
+
+  // Ensure it appears at least once first
+  await page.waitForSelector(selector, { state: 'visible' })
+
+  // Start polling to confirm it stays visible
+  while (Date.now() - start < durationMs) {
+    const isVisible = await page.isVisible(selector)
+
+    if (!isVisible) {
+      throw new Error(`Element "${selector}" disappeared during the visibility duration.`)
+    }
+
+    await new Promise((res) => setTimeout(res, pollIntervalMs))
+  }
+
+  console.log(`Element "${selector}" remained visible for ${durationMs}ms.`)
+}

test/helpers/e2e/assertRequestBody.ts

@@ -21,7 +21,7 @@ import { expect } from '@playwright/test'
 export const assertRequestBody = async <T>(
   page: Page,
   options: {
-    action: Promise<void> | void
+    action: () => Promise<void> | void
     expect?: (requestBody: T) => boolean | Promise<boolean>
     requestMethod?: string
     url: string
@@ -34,7 +34,7 @@ export const assertRequestBody = async <T>(
           (request.method() === options.requestMethod || 'POST'),
       ),
     ),
-    await options.action,
+    await options.action(),
   ])
 
   const requestBody = request.postData()