Reduce flakiness in several tests (#1487)

"does not fire turbo:load twice after following a redirect"
src/tests/functional/navigation_tests.js:451

  The event can sometimes arrive slightly before the check. Count
  events over the whole scenario rather than checking at a specific
  moment, which is more robust and more closely matches the purpose
  of the test.

"link method form submission targeting frame submits a single request"
src/tests/functional/form_submission_tests.js:1019

  Redirect accounting differs between browsers—Firefox sometimes
  won't count the redirect as a request, returning just 1. Stop
  counting redirect requests. Instead, assert the redirect happened
  by checking that the page contains content from the redirect
  target, then verify a single request was made by counting only
  the non-redirect requests.

"successfully following a link to a page without a matching frame
shows an error and throws an exception"
src/tests/functional/frame_tests.js:152

"failing to follow a link to a page without a matching frame shows
an error and throws an exception"
src/tests/functional/frame_tests.js:181

  The assertion on the error can run before the error-setting
  callback runs. Wait for the error to be set and the page click
  to finish before continuing with assertions.

"reloads when tracked elements change"
src/tests/functional/rendering_tests.js:48

  Since we're triggering a full page reload, it's possible to try
  to evaluate on the page at the moment of navigation. This leads
  to a race condition where the check is triggered as the page is
  being navigated away and the evaluation happens after its context
  was already destroyed, throwing "Execution context was destroyed,
  most likely because of a navigation". Use Playwright's native
  page.waitForURL instead of waiting for the turbo:load event,
  since it doesn't rely on page evaluation and is resistant to
  navigation issues.

Author: radanskoric

src/tests/functional/form_submission_tests.js

@@ -1018,15 +1018,18 @@ test("link method form submission inside frame submits a single request", async
 
 test("link method form submission targeting frame submits a single request", async ({ page }) => {
   let requestCounter = 0
-  page.on("request", () => requestCounter++)
+  page.on("request", (request) => {
+    if (request.url().includes("/__turbo/redirect")) requestCounter++
+  })
 
   await page.click("#turbo-method-post-to-targeted-frame")
 
   const { fetchOptions } = await nextEventNamed(page, "turbo:before-fetch-request")
 
   await noNextEventNamed(page, "turbo:before-fetch-request")
   expect(fetchOptions.method, "[data-turbo-method] overrides the GET method").toEqual("POST")
-  expect(requestCounter, "submits a single HTTP request then follows a redirect").toEqual(2)
+  await expect(page.locator("#hello h2")).toHaveText("Hello from a frame")
+  expect(requestCounter, "submits a single HTTP request").toEqual(1)
 })
 
 test("link method form submission inside frame", async ({ page }) => {

src/tests/functional/frame_tests.js

@@ -152,10 +152,10 @@ test("successfully following a link to a page without a matching frame dispatche
 test("successfully following a link to a page without a matching frame shows an error and throws an exception", async ({
   page
 }) => {
-  let error = undefined
-  page.once("pageerror", (e) => (error = e))
-
-  await page.click("#missing-frame-link")
+  const [error] = await Promise.all([
+    page.waitForEvent("pageerror"),
+    page.click("#missing-frame-link")
+  ])
 
   await expect(page.locator("#missing")).toHaveText("Content missing")
 
@@ -184,10 +184,10 @@ test("failing to follow a link to a page without a matching frame dispatches a t
 test("failing to follow a link to a page without a matching frame shows an error and throws an exception", async ({
   page
 }) => {
-  let error = undefined
-  page.once("pageerror", (e) => (error = e))
-
-  await page.click("#missing-page-link")
+  const [error] = await Promise.all([
+    page.waitForEvent("pageerror"),
+    page.click("#missing-page-link")
+  ])
 
   await expect(page.locator("#missing")).toHaveText("Content missing")
 

src/tests/functional/navigation_tests.js

@@ -449,15 +449,21 @@ test("double-clicking on a link", async ({ page }) => {
 })
 
 test("does not fire turbo:load twice after following a redirect", async ({ page }) => {
+  await page.evaluate(() => {
+    window.turboLoadCount = 0
+    addEventListener("turbo:load", () => window.turboLoadCount++)
+  })
+
   page.click("#redirection-link")
 
   await nextBeat() // 301 redirect response
 
-  expect(await noNextEventNamed(page, "turbo:load")).toEqual(true)
-
   await nextBeat() // 200 response
   await nextBody(page)
   await nextEventNamed(page, "turbo:load")
+  await nextBeat()
+
+  expect(await page.evaluate(() => window.turboLoadCount)).toEqual(1)
 })
 
 test("navigating back whilst a visit is in-flight", async ({ page }) => {