Some improvements

tests/Feature/GameSnapshotTest.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Feature;
+
+use App\Events\GameSnapshot;
+use App\Game\Room;
+use PHPUnit\Framework\Attributes\Test;
+use Tests\TestCase;
+
+final class GameSnapshotTest extends TestCase
+{
+    #[Test]
+    public function broadcast_payload_discloses_message_size_cap(): void
+    {
+        $room = new Room('test');
+
+        $payload = (new GameSnapshot($room, [], [], []))->broadcastWith();
+
+        $this->assertArrayHasKey('msgCap', $payload);
+        $this->assertSame(
+            (int) config('reverb.apps.apps.0.max_message_size', 0),
+            $payload['msgCap'],
+            'client debug HUD reports the same cap the Reverb server enforces',
+        );
+    }
+}

tests/Feature/GameStressTestTest.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Feature;
+
+use PHPUnit\Framework\Attributes\Test;
+use Tests\TestCase;
+
+final class GameStressTestTest extends TestCase
+{
+    #[Test]
+    public function unknown_scenario_rejects_with_failure(): void
+    {
+        $this->artisan('game:stress', ['--scenario' => 'aliens'])
+            ->expectsOutputToContain('Unknown scenario')
+            ->assertExitCode(1);
+    }
+
+    #[Test]
+    public function step_below_one_rejects_with_failure(): void
+    {
+        $this->artisan('game:stress', ['--step' => '0'])
+            ->expectsOutputToContain('Invalid sweep range')
+            ->assertExitCode(1);
+    }
+
+    #[Test]
+    public function inverted_range_rejects_with_failure(): void
+    {
+        $this->artisan('game:stress', ['--entities-from' => '200', '--entities-to' => '100'])
+            ->expectsOutputToContain('Invalid sweep range')
+            ->assertExitCode(1);
+    }
+
+    #[Test]
+    public function breakpoint_run_reports_capacity_limits(): void
+    {
+        $this->artisan('game:stress', [
+            '--entities-from' => '50',
+            '--entities-to' => '50',
+            '--step' => '50',
+            '--ticks' => '5',
+            '--breakpoint-only' => true,
+        ])
+            ->expectsOutputToContain('Derived capacity limits')
+            ->expectsOutputToContain('Reverb cap')
+            ->assertExitCode(0);
+    }
+}

tests/Unit/Game/StressTestHarnessTest.php

@@ -0,0 +1,76 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Game;
+
+use App\Game\StressTestHarness;
+use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\TestCase;
+
+final class StressTestHarnessTest extends TestCase
+{
+    private function harness(): StressTestHarness
+    {
+        return new StressTestHarness;
+    }
+
+    #[Test]
+    public function tick_report_has_expected_shape(): void
+    {
+        $report = $this->harness()->measureTickTime(50, players: 2, ticks: 20);
+
+        $this->assertSame(50, $report['entities']);
+        $this->assertArrayHasKey('zombies', $report['scenarios']);
+        $this->assertArrayHasKey('projectiles', $report['scenarios']);
+        foreach ($report['scenarios'] as $result) {
+            $this->assertArrayHasKey('avgMs', $result);
+            $this->assertArrayHasKey('medianMs', $result);
+            $this->assertArrayHasKey('maxMs', $result);
+            $this->assertArrayHasKey('budgetOk', $result);
+        }
+    }
+
+    #[Test]
+    public function tick_time_is_measured_as_positive(): void
+    {
+        $report = $this->harness()->measureTickTime(50, players: 2, ticks: 20);
+
+        foreach ($report['scenarios'] as $result) {
+            $this->assertGreaterThan(0.0, $result['avgMs']);
+            $this->assertGreaterThan(0.0, $result['maxMs']);
+        }
+    }
+
+    #[Test]
+    public function snapshot_bytes_grow_with_entity_count(): void
+    {
+        $small = $this->harness()->measureSnapshotBytes(50, players: 2, scenarios: ['zombies']);
+        $large = $this->harness()->measureSnapshotBytes(400, players: 2, scenarios: ['zombies']);
+
+        $this->assertGreaterThan(
+            $small['scenarios']['zombies']['bytes'],
+            $large['scenarios']['zombies']['bytes'],
+            'snapshot payload should grow as entity count grows',
+        );
+    }
+
+    #[Test]
+    public function snapshot_report_tracks_bytes_per_entity(): void
+    {
+        $report = $this->harness()->measureSnapshotBytes(100, players: 2, scenarios: ['zombies']);
+
+        $this->assertGreaterThan(0, $report['scenarios']['zombies']['bytes']);
+        $this->assertGreaterThan(0.0, $report['scenarios']['zombies']['bytesPerEntity']);
+    }
+
+    #[Test]
+    public function reverb_cap_flag_flips_between_small_and_large_rooms(): void
+    {
+        $small = $this->harness()->measureSnapshotBytes(50, players: 2, scenarios: ['zombies']);
+        $large = $this->harness()->measureSnapshotBytes(2000, players: 2, scenarios: ['zombies']);
+
+        $this->assertFalse($small['scenarios']['zombies']['exceedsReverb']);
+        $this->assertTrue($large['scenarios']['zombies']['exceedsReverb']);
+    }
+}