add test

tests/Feature/ModVersionTest.php

@@ -0,0 +1,34 @@
+<?php
+
+use App\Models\ModVersion;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Carbon;
+
+it('includes only published mod versions', function () {
+    $publishedMod = ModVersion::factory()->create([
+        'published_at' => Carbon::now()->subDay(),
+    ]);
+    $unpublishedMod = ModVersion::factory()->create([
+        'published_at' => Carbon::now()->addDay(),
+    ]);
+    $noPublishedDateMod = ModVersion::factory()->create([
+        'published_at' => null,
+    ]);
+
+    $mods = ModVersion::all();
+
+    expect($mods)->toHaveCount(2);
+    expect($mods->contains($publishedMod))->toBeTrue();
+    expect($mods->contains($unpublishedMod))->toBeFalse();
+    expect($mods->contains($noPublishedDateMod))->toBeTrue();
+});
+
+it('handles null published_at as not published', function () {
+    $modWithNoPublishDate = ModVersion::factory()->create([
+        'published_at' => null,
+    ]);
+
+    $mods = ModVersion::all();
+
+    expect($mods->contains($modWithNoPublishDate))->toBeTrue();
+});