wait for initial hydration

test/development/acceptance/helpers.ts

@@ -6,6 +6,22 @@ import {
 } from 'next-test-utils'
 import webdriver from 'next-webdriver'
 import { NextInstance } from 'test/lib/next-modes/base'
+import { BrowserInterface } from 'test/lib/browsers/base'
+
+function waitForHydration(browser: BrowserInterface): Promise<void> {
+  return browser.evalAsync(function () {
+    var callback = arguments[arguments.length - 1]
+    if ((window as any).__NEXT_HYDRATED) {
+      callback()
+    } else {
+      var timeout = setTimeout(callback, 30 * 1000)
+      ;(window as any).__NEXT_HYDRATED_CB = function () {
+        clearTimeout(timeout)
+        callback()
+      }
+    }
+  })
+}
 
 export async function sandbox(
   next: NextInstance,
@@ -30,6 +46,7 @@ export async function sandbox(
   }
   await next.start()
   const browser = await webdriver(next.url, '/')
+  await waitForHydration(browser)
   return {
     session: {
       async write(filename, content) {
@@ -58,18 +75,7 @@ export async function sandbox(
             await new Promise((resolve) => setTimeout(resolve, 750))
 
             // Wait for application to re-hydrate:
-            await browser.evalAsync(function () {
-              var callback = arguments[arguments.length - 1]
-              if ((window as any).__NEXT_HYDRATED) {
-                callback()
-              } else {
-                var timeout = setTimeout(callback, 30 * 1000)
-                ;(window as any).__NEXT_HYDRATED_CB = function () {
-                  clearTimeout(timeout)
-                  callback()
-                }
-              }
-            })
+            await waitForHydration(browser)
 
             console.log('Application re-loaded.')
             // Slow down tests a bit: