From 7abcc7c5f58e9db006d5b53bbd20a8c3eb031f9d Mon Sep 17 00:00:00 2001
From: Andreas Reinhold / reini <reini@kadenpartner.ch>
Date: Tue, 15 Sep 2026 05:50:55 +0200
Subject: [PATCH] Pin the carousel showcase's viewport and de-flake one
 assertScript
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Found running the full browser suite for plan step 38's last batch,
unrelated to its content changes (confirmed by reverting every
touched file and reproducing both failures against the pre-batch
commit): CarouselTest never pinned a window size, so the multi-browse
row's keyline math only lined "scroll by 2 slots" up with the open
keyline at some widths — the host's own default (here, wider than the
carousel was ever exercised at) left a remainder large enough to fail
four assertions. carouselShowcase() now resizes to 1280x900, matching
the width other browser tests already treat as "large desktop".

One test still failed after that: it put a `.click()` inside the
script assertScript asserts, and assertScript retries its whole
expression on a false result (this file's own comment says so) — a
retry re-fires the click, drifting the carousel one item further each
time and never recovering, unlike every other test here, which clicks
through a separate call first. Split the click out the same way.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9
---
 tests/Browser/CarouselTest.php | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/tests/Browser/CarouselTest.php b/tests/Browser/CarouselTest.php
index 54f548ce..d6e0fe01 100644
--- a/tests/Browser/CarouselTest.php
+++ b/tests/Browser/CarouselTest.php
@@ -70,7 +70,11 @@ const FIRST_ITEM = '#carousel [data-md-carousel-item] >> nth=0';
 
 function carouselShowcase(array $options = [])
 {
+    // Pinned rather than left to the host's own window: at a wide enough viewport the multi-browse
+    // row's 8 items (220px each) leave a remainder the keyline math does not reduce to zero the way
+    // it does here, so "scroll by exactly 2 slots" no longer lands item 2 on the open keyline.
     return visit('/material/carousel', $options)
+        ->resize(1280, 900)
         ->waitForEvent('networkidle')
         ->assertScript("typeof window.Alpine !== 'undefined'");
 }
@@ -164,14 +168,18 @@ it('brings a partly hidden item into focus when it is pressed, and leaves an ope
 });
 
 it('scrolls instantly and leaves every item unmasked under reduced motion', function () {
-    carouselShowcase(['reducedMotion' => 'reduce'])
-        ->assertScript(onCarousel(0, <<<'JS'
-            root.querySelector('[aria-label="Next"]').click()
-            const arrived = at(1)
-            await pause(50)
-            return arrived && items.every((_, i) => inset(i) === 0)
-                && items.every((item) => Math.abs(item.getBoundingClientRect().width - size) < 1.5)
-            JS));
+    // A click, then a separate read-only assertScript: assertScript retries its whole expression
+    // on a false result (this file's own comment above), and a click inside it would fire again on
+    // every retry, drifting the carousel one further item each time and never recovering.
+    $page = carouselShowcase(['reducedMotion' => 'reduce']);
+
+    $page->script(onCarousel(0, 'root.querySelector(\'[aria-label="Next"]\').click()'));
+
+    $page->assertScript(onCarousel(0, <<<'JS'
+        await pause(50)
+        return at(1) && items.every((_, i) => inset(i) === 0)
+            && items.every((item) => Math.abs(item.getBoundingClientRect().width - size) < 1.5)
+        JS));
 });
 
 it('brings an item cut off at the row\'s edge into view when it is pressed under reduced motion', function () {