diff --git a/CHANGELOG.md b/CHANGELOG.md
index 324b47b..c43f6bc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@ All notable changes to `pollora/hook` are documented in this file.
 - `unique()`: merge identical triggers (same hook, same handler, same arguments) while the first one has not started running. The lock is an option that is not autoloaded, taken atomically with `add_option()`, released when the first attempt starts, and expiring after `unique(for: …)` seconds (one day by default) if never released; the daily maintenance task deletes expired locks. A lock that cannot be stored is a queuing failure, never a silent merge.
 - `action-scheduler` driver, offered when a plugin bundling Action Scheduler is active and its data store is initialised (never a dependency). The payload travels whole as the action argument, the queue name becomes the group (`pollora` by default), and history is visible in Tools › Scheduled Actions. A payload too long for Action Scheduler's arguments (8,000 characters as JSON) is kept in an option that is not autoloaded and the action carries only its identifier.
 - `Async::setAutoDrivers()`: the drivers `auto` tries, in order.
+- `Async::fake()` for tests: records queued handlers instead of queuing them, whatever the driver, with `Async::assertDispatched()` (by class, descriptor or `closure`, with an optional callback receiving the payload and the delay), `assertDispatchedTimes()`, `assertNotDispatched()` and `assertNothingDispatched()`. Arguments are still normalized, so one that cannot travel fails here too; `runDispatched()` runs the recorded handlers. Assertions go through PHPUnit when it is installed.
 - Closures as asynchronous handlers, when `laravel/serializable-closure` is installed (suggested, not required). The closure is serialized with it and signed with an HMAC-SHA256 whose key derives from `wp_salt('auth')`, or is set with `Async::useClosureKey()`; the signature is checked before anything is unserialized, and an altered payload or a changed key fails with an explicit report. The closure is checked at registration but signed when its hook first fires, since `wp_salt()` is pluggable and not loaded while plugins load. A closure made from a named function or method (`strlen(...)`, `$object->method(...)`) travels by that name.
 - Payloads record the driver that queued them, the queue, `asUser`, the backoff and the unique lock. These fields are optional, so payloads queued by 1.2.0 still run.
 
diff --git a/src/Async/Async.php b/src/Async/Async.php
index 19c11c5..e1acc34 100644
--- a/src/Async/Async.php
+++ b/src/Async/Async.php
@@ -56,6 +56,8 @@ final class Async
 
     private static ?string $closureKey = null;
 
+    private static ?AsyncFake $fake = null;
+
     private static ?ArgumentNormalizer $normalizer = null;
 
     private static ?AsyncDispatcher $dispatcher = null;
@@ -87,6 +89,10 @@ public static function extend(string $name, callable $factory): void
      */
     public static function driver(?string $name = null): AsyncDriver
     {
+        if (self::$fake instanceof AsyncFake) {
+            return self::$fake;
+        }
+
         $name ??= self::defaultDriver();
         $factories = self::factories();
 
@@ -103,6 +109,40 @@ public static function driver(?string $name = null): AsyncDriver
         return $driver;
     }
 
+    /**
+     * Record queued handlers instead of queuing them, whatever the driver. For tests.
+     */
+    public static function fake(): AsyncFake
+    {
+        return self::$fake = new AsyncFake;
+    }
+
+    /**
+     * @param  (callable(AsyncPayload, int): bool)|null  $callback  Receives the payload and its delay
+     */
+    public static function assertDispatched(string $handler, ?callable $callback = null): void
+    {
+        self::faked()->assertDispatched($handler, $callback);
+    }
+
+    public static function assertDispatchedTimes(string $handler, int $times): void
+    {
+        self::faked()->assertDispatchedTimes($handler, $times);
+    }
+
+    /**
+     * @param  (callable(AsyncPayload, int): bool)|null  $callback
+     */
+    public static function assertNotDispatched(string $handler, ?callable $callback = null): void
+    {
+        self::faked()->assertNotDispatched($handler, $callback);
+    }
+
+    public static function assertNothingDispatched(): void
+    {
+        self::faked()->assertNothingDispatched();
+    }
+
     /**
      * Name of the default driver, from the first of: setDefaultDriver(), the
      * POLLORA_ASYNC_DRIVER constant, the 'pollora/hook/async_driver' filter,
@@ -315,6 +355,7 @@ public static function flush(): void
         self::$autoDrivers = ['action-scheduler', 'wp-cron'];
         self::$resolver = null;
         self::$closureKey = null;
+        self::$fake = null;
         self::$normalizer = null;
         self::$dispatcher = null;
         self::$runner = null;
@@ -322,6 +363,11 @@ public static function flush(): void
         self::$reporter = null;
     }
 
+    private static function faked(): AsyncFake
+    {
+        return self::$fake ?? throw new \LogicException('Call Async::fake() before asserting on dispatched handlers.');
+    }
+
     /**
      * The first available auto driver, WP-Cron when none is.
      */
diff --git a/src/Async/AsyncFake.php b/src/Async/AsyncFake.php
new file mode 100644
index 0000000..bfcf266
--- /dev/null
+++ b/src/Async/AsyncFake.php
@@ -0,0 +1,124 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Pollora\Hook\Async;
+
+use PHPUnit\Framework\Assert;
+use Pollora\Hook\Async\Contracts\AsyncDriver;
+
+/**
+ * Records queued handlers instead of queuing them, for tests.
+ *
+ *     Async::fake();
+ *     wp_update_post(['ID' => $event->ID, 'post_title' => 'New title']);
+ *     Async::assertDispatched(SyncEventToCrm::class, fn (AsyncPayload $payload) => $payload->captured['status'] === 'publish');
+ *
+ * Arguments and captured values are normalized as for a real driver, so one
+ * that cannot travel fails here too. A handler is matched by its class name,
+ * its descriptor ('Class@method', a function name), or 'closure' for closures.
+ */
+final class AsyncFake implements AsyncDriver
+{
+    /** @var list<array{payload: AsyncPayload, delay: int}> */
+    private array $dispatched = [];
+
+    public function available(): bool
+    {
+        return true;
+    }
+
+    public function dispatch(AsyncPayload $payload, int $delay = 0): void
+    {
+        $this->dispatched[] = ['payload' => $payload, 'delay' => $delay];
+    }
+
+    /**
+     * Payloads recorded for a handler, or all of them.
+     *
+     * @param  (callable(AsyncPayload, int): bool)|null  $callback  Receives the payload and its delay
+     * @return list<AsyncPayload>
+     */
+    public function dispatched(?string $handler = null, ?callable $callback = null): array
+    {
+        $payloads = [];
+
+        foreach ($this->dispatched as $entry) {
+            if ($handler !== null && ! self::matches($entry['payload'], $handler)) {
+                continue;
+            }
+
+            if ($callback !== null && $callback($entry['payload'], $entry['delay']) !== true) {
+                continue;
+            }
+
+            $payloads[] = $entry['payload'];
+        }
+
+        return $payloads;
+    }
+
+    /**
+     * @param  (callable(AsyncPayload, int): bool)|null  $callback
+     */
+    public function assertDispatched(string $handler, ?callable $callback = null): void
+    {
+        self::assert(
+            $this->dispatched($handler, $callback) !== [],
+            sprintf('The asynchronous handler [%s] was not dispatched%s.', $handler, $callback === null ? '' : ' with the expected payload'),
+        );
+    }
+
+    public function assertDispatchedTimes(string $handler, int $times): void
+    {
+        $count = count($this->dispatched($handler));
+
+        self::assert($count === $times, sprintf('The asynchronous handler [%s] was dispatched %d time(s) instead of %d.', $handler, $count, $times));
+    }
+
+    /**
+     * @param  (callable(AsyncPayload, int): bool)|null  $callback
+     */
+    public function assertNotDispatched(string $handler, ?callable $callback = null): void
+    {
+        self::assert($this->dispatched($handler, $callback) === [], sprintf('The asynchronous handler [%s] was dispatched.', $handler));
+    }
+
+    public function assertNothingDispatched(): void
+    {
+        self::assert($this->dispatched === [], sprintf('%d asynchronous handler(s) were dispatched.', count($this->dispatched)));
+    }
+
+    /**
+     * Run the recorded handlers, as a driver would, then forget them.
+     */
+    public function runDispatched(): void
+    {
+        while ($this->dispatched !== []) {
+            $entry = array_shift($this->dispatched);
+            Async::receive($entry['payload']->toJson());
+        }
+    }
+
+    private static function matches(AsyncPayload $payload, string $handler): bool
+    {
+        $handler = ltrim($handler, '\\');
+
+        return $payload->handler === $handler
+            || str_starts_with($payload->handler, $handler.'@')
+            || ($handler === 'closure' && str_starts_with($payload->handler, 'closure:'));
+    }
+
+    private static function assert(bool $condition, string $message): void
+    {
+        if (class_exists(Assert::class)) {
+            Assert::assertTrue($condition, $message);
+
+            return;
+        }
+
+        if (! $condition) {
+            throw new \AssertionError($message);
+        }
+    }
+}
diff --git a/tests/Unit/Async/FakeTest.php b/tests/Unit/Async/FakeTest.php
new file mode 100644
index 0000000..33dd34a
--- /dev/null
+++ b/tests/Unit/Async/FakeTest.php
@@ -0,0 +1,129 @@
+<?php
+
+declare(strict_types=1);
+
+use PHPUnit\Framework\AssertionFailedError;
+use Pollora\Hook\Adapter\Out\WordPress\Action;
+use Pollora\Hook\Async\Async;
+use Pollora\Hook\Async\AsyncFake;
+use Pollora\Hook\Async\AsyncPayload;
+use Pollora\Hook\Async\Exceptions\UnsupportedArgument;
+use Pollora\Hook\Tests\Fixtures\Async\RecordingHandler;
+
+beforeEach(function (): void {
+    $GLOBALS['wp_actions'] = [];
+    $GLOBALS['wp_async_listeners'] = [];
+    $GLOBALS['wp_options'] = [];
+    $GLOBALS['wp_cron_events'] = [];
+    $GLOBALS['wp_state'] = ['user' => 5, 'blog' => 1, 'locale' => 'fr_FR', 'multisite' => false];
+    $GLOBALS['wp_objects'] = [];
+    RecordingHandler::$calls = [];
+    RecordingHandler::$failuresLeft = 0;
+
+    Async::flush();
+    Async::setDebug(true);
+    $this->fake = Async::fake();
+    $this->action = new Action;
+});
+
+afterEach(function (): void {
+    Async::flush();
+});
+
+it('records queued handlers instead of queuing them, whatever the driver', function (): void {
+    $this->action->add('save_post', [RecordingHandler::class, 'handle'])->async();
+    $this->action->add('edit_post', [RecordingHandler::class, 'handle'])->async()->via('rabbitmq');
+
+    wp_stub_fire('save_post', 1);
+    wp_stub_fire('edit_post', 2);
+
+    expect($this->fake)->toBeInstanceOf(AsyncFake::class)
+        ->and($this->fake->dispatched())->toHaveCount(2)
+        ->and($GLOBALS['wp_cron_events'])->toBe([])
+        ->and(RecordingHandler::$calls)->toBe([]);
+});
+
+it('asserts on a handler by class, descriptor or payload, as in the design document', function (): void {
+    $GLOBALS['wp_objects']['post'][12] = new WP_Post(12, 'publish');
+    $this->action->add('save_post', [RecordingHandler::class, 'post'])->async()
+        ->capture(fn (WP_Post $post): array => ['status' => $post->post_status]);
+
+    wp_stub_fire('save_post', new WP_Post(12, 'publish'));
+
+    Async::assertDispatched(RecordingHandler::class);
+    Async::assertDispatched(RecordingHandler::class.'@post');
+    Async::assertDispatched(RecordingHandler::class, fn (AsyncPayload $payload): bool => $payload->captured['status'] === 'publish');
+    Async::assertDispatchedTimes(RecordingHandler::class, 1);
+    Async::assertNotDispatched(RecordingHandler::class.'@handle');
+});
+
+it('fails an assertion that does not hold, with a readable message', function (Closure $assertion, string $message): void {
+    $this->action->add('save_post', [RecordingHandler::class, 'handle'])->async();
+    wp_stub_fire('save_post', 1);
+
+    expect($assertion)->toThrow(AssertionFailedError::class, $message);
+})->with([
+    'not dispatched' => [fn () => Async::assertDispatched('App\Missing'), 'The asynchronous handler [App\Missing] was not dispatched.'],
+    'wrong payload' => [fn () => Async::assertDispatched(RecordingHandler::class, fn (): bool => false), 'was not dispatched with the expected payload'],
+    'wrong count' => [fn () => Async::assertDispatchedTimes(RecordingHandler::class, 2), 'dispatched 1 time(s) instead of 2'],
+    'dispatched' => [fn () => Async::assertNotDispatched(RecordingHandler::class), 'was dispatched'],
+    'something dispatched' => [fn () => Async::assertNothingDispatched(), '1 asynchronous handler(s) were dispatched'],
+]);
+
+it('hands the delay to the callback', function (): void {
+    $this->action->add('save_post', [RecordingHandler::class, 'handle'])->async()->delay(90);
+
+    wp_stub_fire('save_post', 1);
+
+    Async::assertDispatched(RecordingHandler::class, fn (AsyncPayload $payload, int $delay): bool => $delay === 90);
+});
+
+it('matches closures', function (): void {
+    Async::useClosureKey('test-signing-key');
+    $this->action->add('save_post', static function (int $postId): void {})->async();
+
+    wp_stub_fire('save_post', 1);
+
+    Async::assertDispatched('closure');
+});
+
+it('does not record a trigger that when() skips', function (): void {
+    $this->action->add('save_post', [RecordingHandler::class, 'handle'])->async()->when(fn (): bool => false);
+
+    wp_stub_fire('save_post', 1);
+
+    Async::assertNothingDispatched();
+});
+
+it('still rejects an argument that cannot travel', function (): void {
+    $this->action->add('save_post', [RecordingHandler::class, 'objects'])->async();
+
+    expect(fn () => wp_stub_fire('save_post', new stdClass))->toThrow(UnsupportedArgument::class);
+});
+
+it('runs the recorded handlers on demand, retries included', function (): void {
+    RecordingHandler::$failuresLeft = 1;
+    $this->action->add('save_post', [RecordingHandler::class, 'flaky'])->async()->tries(2);
+    wp_stub_fire('save_post', 4);
+
+    $this->fake->runDispatched();
+
+    expect(array_column(RecordingHandler::$calls, 'arguments'))->toBe([[4, 1], [4, 2]])
+        ->and($this->fake->dispatched())->toBe([]);
+});
+
+it('requires fake() before asserting', function (): void {
+    Async::flush();
+
+    expect(fn () => Async::assertNothingDispatched())->toThrow(LogicException::class, 'Call Async::fake()');
+});
+
+it('is forgotten by flush()', function (): void {
+    Async::flush();
+    Async::setDefaultDriver('sync');
+    $this->action->add('save_post', [RecordingHandler::class, 'handle'])->async();
+
+    wp_stub_fire('save_post', 1);
+
+    expect(RecordingHandler::$calls)->toHaveCount(1);
+});
diff --git a/tests/WordPress/AsyncWpCronTest.php b/tests/WordPress/AsyncWpCronTest.php
index 0626047..e3134af 100644
--- a/tests/WordPress/AsyncWpCronTest.php
+++ b/tests/WordPress/AsyncWpCronTest.php
@@ -3,6 +3,7 @@
 declare(strict_types=1);
 
 use Pollora\Hook\Async\Async;
+use Pollora\Hook\Async\AsyncPayload;
 use Pollora\Hook\Async\Drivers\WpCronDriver;
 
 /*
@@ -224,3 +225,16 @@ function fixtureRuns(): array
     expect(array_column($runs, 'key'))->toBe(['failed'])
         ->and($runs[0]['message'])->toContain('signature of a queued closure is invalid');
 });
+
+it('records handlers with Async::fake() instead of queuing them', function (): void {
+    Async::fake();
+
+    try {
+        do_action('pollora_fixture_event', $this->postId, get_post($this->postId));
+
+        Async::assertDispatched(PolloraHookFixture::class.'@event', fn (AsyncPayload $payload): bool => $payload->arguments[0] === $this->postId);
+        expect(scheduledExecutions())->toBe([]);
+    } finally {
+        Async::flush();
+    }
+});