Merge pull request 'test(e2e): make the resend allowance failure say why (#257)' (#319) from fix/257-resend-verification-flake into main

Reviewed-on: #319

frontend/tests/e2e/resend-verification.spec.ts

@@ -22,24 +22,70 @@ test.describe('Resending your verification email', () => {
   // The message the customer gets on the fourth attempt is the point of the
   // limiter's copy: it says the mail probably did send and where to look,
   // rather than only that a limit exists.
+  //
+  // ## Why this asserts on responses rather than on what is on screen (#257)
+  //
+  // This test failed roughly one full-suite run in three, never in isolation,
+  // with a strict-mode violation: `getByText(/already sent several/)` resolved
+  // to three refusal toasts where one was expected. Two investigations could
+  // not establish why, and the second corrected the arithmetic the first
+  // relied on — antd toasts auto-dismiss, so **the number visible at the moment
+  // of an assertion is a lower bound on how many refusals happened, not a
+  // count**. Three visible refusals is equally consistent with four where the
+  // first had already faded.
+  //
+  // That makes toast-counting the wrong instrument twice over: it is
+  // timing-dependent, and `toBeVisible()` on a multi-match locator fails in
+  // strict mode even when the behaviour was correct. The responses are the
+  // behaviour; the toasts are a lossy rendering of it.
+  //
+  // So the sequence of statuses is recorded and asserted directly. If this
+  // fails again it now says which failure it is, which is exactly what #257
+  // could not determine: `[429, 429, 429, 429]` means the customer's bucket
+  // already held hits before the test clicked anything, while more than four
+  // entries means the UI sent more requests than there were clicks. Either
+  // answer identifies the mechanism from a single failing run, rather than
+  // needing a temporary probe re-added and the suite run until it fails again.
   test('says something useful once the allowance runs out', async ({
     page,
     customer,
     accountModal
   }) => {
+    const isResend = (url: string) =>
+      new URL(url).pathname === '/api/customers/resend-verification';
+
+    // Recorded from the first navigation onward, deliberately: a request the
+    // test did not make is one of the explanations still open, and a recorder
+    // installed after the clicks could not see it.
+    const statuses: number[] = [];
+    page.on('response', (res) => {
+      if (isResend(res.url())) statuses.push(res.status());
+    });
+
     await accountModal.open();
 
     const resend = accountModal.resendVerificationButton;
-    for (let i = 0; i < 3; i++) {
+    // Each click waits for its own response before the next. The previous
-      await resend.click();
+    // `await expect(resend).toBeEnabled()` looked like pacing but was a no-op —
-      await expect(resend).toBeEnabled();
+    // the button is never disabled, so it returned immediately and left four
+    // requests racing. Waiting on the response removes concurrency as a
+    // variable, so a failure here cannot be explained by ordering.
+    for (let i = 0; i < 4; i++) {
+      await Promise.all([
+        page.waitForResponse((res) => isResend(res.url())),
+        resend.click()
+      ]);
     }
 
-    await resend.click();
+    // The allowance is three an hour, so three sends and one refusal. The
+    // message names the customer because a bucket carrying hits from somewhere
+    // else is the open question, and the address is what identifies whose.
+    expect(statuses, `resend responses for ${customer.email}`).toEqual([204, 204, 204, 429]);
 
-    // Matched on the phrase unique to the refusal. "spam folder" appears in the
+    // The copy itself still matters — it is what this test is named for. Scoped
-    // success message too, and the three stacked success toasts from the loop
+    // with `.first()` because strict mode treats several identical toasts as
-    // above are still on screen, so the looser match finds them instead.
+    // ambiguous, and how many are still on screen is a timing detail this
-    await expect(page.getByText(/already sent several/)).toBeVisible();
+    // assertion should not depend on.
+    await expect(page.getByText(/already sent several/).first()).toBeVisible();
   });
 });