Press once whatever a second press would open over or undo

The browser plugin runs every call on a page again when its first
attempt takes over a second, and on the runner a press can. For most
presses that costs nothing. For two kinds it breaks the test: a press
that opens a dialog, a sheet, a full-screen view or a modal rail over
its own trigger, whose second press can never land, and a press that
changes state a second one would change again — a menu trigger, a
toggle, a chip, a range picker's day, a paging key, a Save. The bottom
sheet with preset heights timed out on WebKit that way after the date
picker had on Firefox.

Every such press in the browser suite now goes through pressOnce(), 253
of them across sixteen files, not only the ones the runner happened to
catch; focus moves inside an open view, Escape, links and plain "set"
actions keep the retry, which is harmless for them.

Two samples that were still racing the machine:

- The standard side sheet's exit is caught half-way with its motion
  stretched, as every other mid-exit sample is, and fullSpeed() takes
  the stretch off again before the test times a reopen against the real
  exit. Under load on Linux WebKit it had failed two runs in five; it
  passes ten in ten.
- The switch-and-checkbox row measures its widths once, so it now waits
  for the resize to land and the brand face to load before it does.

Browser 300 passed on Firefox and WebKitGTK in a Linux container held to
two busy cores, and on Chrome, Firefox and WebKit on macOS. Feature 1159
passed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/Browser/CarouselTest.php

@@ -107,29 +107,37 @@ it('moves one item with the next and previous buttons', function () {
     $page = carouselShowcase()
         ->assertScript(onCarousel(0, 'return at(0) && root.querySelector(\'[aria-label="Previous"]\').disabled'));
 
-    $page->click('#carousel button[aria-label="Next"] >> nth=0')
-        ->assertScript(onCarousel(0, 'return at(1) && inset(1) < 0.5 && !root.querySelector(\'[aria-label="Previous"]\').disabled'));
+    // A retried press drifts the carousel one further item each time: pressOnce(), tests/Pest.php.
+    pressOnce($page)->click('#carousel button[aria-label="Next"] >> nth=0');
 
-    $page->click('#carousel button[aria-label="Next"] >> nth=0')
-        ->assertScript(onCarousel(0, 'return at(2)'));
+    $page->assertScript(onCarousel(0, 'return at(1) && inset(1) < 0.5 && !root.querySelector(\'[aria-label="Previous"]\').disabled'));
 
-    $page->click('#carousel button[aria-label="Previous"] >> nth=0')
-        ->assertScript(onCarousel(0, 'return at(1)'));
+    pressOnce($page)->click('#carousel button[aria-label="Next"] >> nth=0');
+
+    $page->assertScript(onCarousel(0, 'return at(2)'));
+
+    pressOnce($page)->click('#carousel button[aria-label="Previous"] >> nth=0');
+
+    $page->assertScript(onCarousel(0, 'return at(1)'));
 });
 
 it('moves one item with the arrow keys, and to the ends with Home and End', function () {
     $page = carouselShowcase();
 
     // M3 puts the tab stop on the item, so the keys are the focused item's and each one moves
-    // focus to the item it scrolls to.
-    $page->keys(FIRST_ITEM, 'ArrowRight')
-        ->assertScript(onCarousel(0, 'return at(1) && document.activeElement === items[1]'));
+    // focus to the item it scrolls to. A retried press drifts the carousel one further item each
+    // time: pressOnce(), tests/Pest.php.
+    pressOnce($page)->keys(FIRST_ITEM, 'ArrowRight');
 
-    $page->keys(':focus', 'ArrowRight')
-        ->assertScript(onCarousel(0, 'return at(2)'));
+    $page->assertScript(onCarousel(0, 'return at(1) && document.activeElement === items[1]'));
 
-    $page->keys(':focus', 'ArrowLeft')
-        ->assertScript(onCarousel(0, 'return at(1)'));
+    pressOnce($page)->keys(':focus', 'ArrowRight');
+
+    $page->assertScript(onCarousel(0, 'return at(2)'));
+
+    pressOnce($page)->keys(':focus', 'ArrowLeft');
+
+    $page->assertScript(onCarousel(0, 'return at(1)'));
 
     $page->keys(':focus', 'End')
         ->assertScript(onCarousel(0, 'return Math.abs(scroller.scrollLeft - (scroller.scrollWidth - scroller.clientWidth)) < 1.5 && open(items.length - 1) && root.querySelector(\'[aria-label="Next"]\').disabled'));
@@ -234,17 +242,21 @@ it('mirrors in a right-to-left page', function () {
         ->assertNoJavaScriptErrors()
         ->assertScript(onCarousel(0, 'return size > 0 && at(0) && open(0) && ! open(items.length - 1)', 'body'));
 
-    $page->keys('[data-md-carousel-item] >> nth=0', 'ArrowLeft')
-        ->assertScript(onCarousel(0, <<<'JS'
+    // A retried press drifts the carousel one further item each time: pressOnce(), tests/Pest.php.
+    pressOnce($page)->keys('[data-md-carousel-item] >> nth=0', 'ArrowLeft');
+
+    $page->assertScript(onCarousel(0, <<<'JS'
             return scroller.scrollLeft < -1 && at(1) && ! open(0) && open(1)
                 && parseFloat(surface(0).style.getPropertyValue('--material-carousel-shift')) < 0
             JS, 'body'));
 
-    $page->click('button[aria-label="Next"]')
-        ->assertScript(onCarousel(0, 'return at(2)', 'body'));
+    pressOnce($page)->click('button[aria-label="Next"]');
 
-    $page->keys('[data-md-carousel-item] >> nth=2', 'ArrowRight')
-        ->assertScript(onCarousel(0, 'return at(1)', 'body'));
+    $page->assertScript(onCarousel(0, 'return at(2)', 'body'));
+
+    pressOnce($page)->keys('[data-md-carousel-item] >> nth=2', 'ArrowRight');
+
+    $page->assertScript(onCarousel(0, 'return at(1)', 'body'));
 });
 
 it('measures itself again after a Livewire morph adds an item', function () {
@@ -273,8 +285,10 @@ it('measures itself again after a Livewire morph adds an item', function () {
         ->assertScript($masked, 6)
         ->assertAttribute('[data-md-carousel-item] >> nth=5', 'aria-label', '6 of 6');
 
-    $page->click('Add')
-        ->assertScript($masked, 7)
+    // A counter a retry would double: pressOnce(), tests/Pest.php.
+    pressOnce($page)->click('Add');
+
+    $page->assertScript($masked, 7)
         ->assertAttribute('[data-md-carousel-item] >> nth=6', 'aria-label', '7 of 7');
 
     // Scrolled once the morph has settled, so only the row's own scroll listener can re-mask the
@@ -316,26 +330,31 @@ it('moves the multi-aspect carousel one item at a time with the buttons, arrows,
         ->assertNoJavaScriptErrors()
         ->assertScript(onMultiAspectCarousel('return scroller.scrollLeft === 0 && items.length > 2'));
 
-    $page->click(MULTI_ASPECT_SCOPE.' button[aria-label="Next"]')
-        ->assertScript(onMultiAspectCarousel(<<<'JS'
+    // A retried press drifts the carousel one further item each time: pressOnce(), tests/Pest.php.
+    pressOnce($page)->click(MULTI_ASPECT_SCOPE.' button[aria-label="Next"]');
+
+    $page->assertScript(onMultiAspectCarousel(<<<'JS'
             await pause(400)
             return scroller.scrollLeft > 0
             JS));
 
-    $page->click(MULTI_ASPECT_SCOPE.' button[aria-label="Previous"]')
-        ->assertScript(onMultiAspectCarousel(<<<'JS'
+    pressOnce($page)->click(MULTI_ASPECT_SCOPE.' button[aria-label="Previous"]');
+
+    $page->assertScript(onMultiAspectCarousel(<<<'JS'
             await pause(400)
             return scroller.scrollLeft === 0
             JS));
 
-    $page->keys(MULTI_ASPECT_SCOPE.' [data-md-carousel-item] >> nth=0', 'ArrowRight')
-        ->assertScript(onMultiAspectCarousel(<<<'JS'
+    pressOnce($page)->keys(MULTI_ASPECT_SCOPE.' [data-md-carousel-item] >> nth=0', 'ArrowRight');
+
+    $page->assertScript(onMultiAspectCarousel(<<<'JS'
             await pause(400)
             return scroller.scrollLeft > 0 && document.activeElement === items[1]
             JS));
 
-    $page->keys(':focus', 'ArrowLeft')
-        ->assertScript(onMultiAspectCarousel(<<<'JS'
+    pressOnce($page)->keys(':focus', 'ArrowLeft');
+
+    $page->assertScript(onMultiAspectCarousel(<<<'JS'
             await pause(400)
             return scroller.scrollLeft === 0 && document.activeElement === items[0]
             JS));