[LiveComponent] Add assert in test live component

src/LiveComponent/doc/index.rst

@@ -3781,6 +3781,11 @@ uses Symfony's test client to render and make requests to your components::
                 ->emit('increaseEvent', ['amount' => 2]) // emit a live event with arguments
             ;
 
+            // Assert that the event was emitted
+            $this->componentHasEmittedEvent($render, 'increaseEvent', [
+                'amount' => 2,
+            ]);
+
             // set live props
             $testComponent
                 ->set('count', 99)

src/LiveComponent/src/Test/InteractsWithLiveComponents.php

@@ -44,4 +44,35 @@ protected function createLiveComponent(string $name, array $data = [], ?KernelBr
             self::getContainer()->get('router'),
         );
     }
+
+    protected function assertComponentEmitEvent(TestLiveComponent $testLiveComponent, string $expectedEventName, ?array $expectedEventData = null): void
+    {
+        $event = $testLiveComponent->getEmittedEvent($testLiveComponent->render(), $expectedEventName);
+
+        $this->assertNotNull($event, \sprintf('The component "%s" did not emit event "%s".', $testLiveComponent->getName(), $expectedEventName));
+
+        if (null === $expectedEventData) {
+            return;
+        }
+
+        foreach ($expectedEventData as $key => $value) {
+            $this->assertArrayHasKey($key, $event['data'], \sprintf('The expected event "%s" data "%s" does not exists', $event['event'], $key));
+            $this->assertSame(
+                $value,
+                $event['data'][$key],
+                \sprintf(
+                    'The expected event "%s" data "%s" expected "%s" but "%s" given',
+                    $event['event'],
+                    $key,
+                    $value,
+                    $event['data'][$key]
+                )
+            );
+        }
+    }
+
+    protected function assertComponentNotEmitEvent(TestLiveComponent $testLiveComponent, string $eventName): void
+    {
+        $this->assertNull($testLiveComponent->getEmittedEvent($testLiveComponent->render(), $eventName), \sprintf('The component "%s" did not emit event "%s".', $testLiveComponent->getName(), $eventName));
+    }
 }

src/LiveComponent/src/Test/TestLiveComponent.php

@@ -229,4 +229,39 @@ private function flattenFormValues(array $values, string $prefix = ''): array
 
         return $result;
     }
+
+    /**
+     * @return ?array{data: array<string, int|float|string|bool|null>, event: non-empty-string}
+     */
+    public function getEmittedEvent(RenderedComponent $render, string $eventName): ?array
+    {
+        $events = $this->getEmittedEvents($render);
+
+        foreach ($events as $event) {
+            if ($event['event'] === $eventName) {
+                return $event;
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * @return array<array{data: array<string, int|float|string|bool|null>, event: non-empty-string}>
+     */
+    public function getEmittedEvents(RenderedComponent $render): array
+    {
+        $emit = $render->crawler()->filter('[data-live-name-value]')->attr('data-live-events-to-emit-value');
+
+        if (null === $emit) {
+            return [];
+        }
+
+        return json_decode($emit, associative: true, flags: \JSON_THROW_ON_ERROR);
+    }
+
+    public function getName(): string
+    {
+        return $this->metadata->getName();
+    }
 }

src/LiveComponent/tests/Functional/Test/InteractsWithLiveComponentsTest.php

@@ -11,6 +11,7 @@
 
 namespace Symfony\UX\LiveComponent\Tests\Functional\Test;
 
+use PHPUnit\Framework\AssertionFailedError;
 use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
 use Symfony\Component\Security\Core\Exception\AccessDeniedException;
 use Symfony\Component\Security\Core\User\InMemoryUser;
@@ -217,4 +218,62 @@ public function testSetLocaleRenderLocalizedComponent(): void
         $testComponent->setRouteLocale('de');
         $this->assertStringContainsString('Locale: de', $testComponent->render());
     }
+
+    public function testComponentEmitsExpectedEventWithExpectedEventData(): void
+    {
+        $testComponent = $this->createLiveComponent('component_with_emit');
+
+        $testComponent->call('actionThatEmits');
+
+        $this->assertComponentEmitEvent($testComponent, 'event1', [
+            'foo' => 'bar',
+        ]);
+    }
+
+    public function testComponentDoesNotEmitUnexpectedEvent(): void
+    {
+        $testComponent = $this->createLiveComponent('component_with_emit');
+
+        $testComponent->call('actionThatEmits');
+
+        $this->assertComponentNotEmitEvent($testComponent, 'event2');
+    }
+
+    public function testComponentDoesNotEmitUnexpectedEventFails(): void
+    {
+        $testComponent = $this->createLiveComponent('component_with_emit');
+
+        $testComponent->call('actionThatEmits');
+
+        $this->expectException(AssertionFailedError::class);
+        $this->expectExceptionMessage('The component "component_with_emit" did not emit event "event1".');
+        $this->assertComponentNotEmitEvent($testComponent, 'event1');
+    }
+
+    public function testComponentEmitsEventWithNotFoundExpectedDataFails(): void
+    {
+        $testComponent = $this->createLiveComponent('component_with_emit');
+
+        $testComponent->call('actionThatEmits');
+
+        $this->expectException(AssertionFailedError::class);
+        $this->expectExceptionMessage('The expected event "event1" data "foo2" does not exists');
+        $this->assertComponentEmitEvent($testComponent, 'event1', [
+            'foo' => 'bar',
+            'foo2' => 'bar2',
+        ]);
+    }
+
+    public function testComponentEmitsEventWithNotValidExpectedDataFails(): void
+    {
+        $testComponent = $this->createLiveComponent('component_with_emit');
+
+        $testComponent->call('actionThatEmits');
+
+        $this->expectException(AssertionFailedError::class);
+        $this->expectExceptionMessage('The expected event "event1" data "foo" expected "bar2" but "bar" given');
+        $this->assertComponentEmitEvent($testComponent, 'event1', [
+            'foo' => 'bar2',
+        ]);
+    }
 }