test set order migration

backend/tests/Feature/SetOrderingMigrationTest.php

@@ -0,0 +1,86 @@
+<?php
+
+namespace Tests\Feature;
+
+use Illuminate\Database\QueryException;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+use Tests\TestCase;
+
+class SetOrderingMigrationTest extends TestCase
+{
+    use RefreshDatabase;
+
+    private const MIGRATION_PATH =
+        'migrations/2026_07_31_000000_add_sort_order_to_sets_table.php';
+
+    public function testBackfillsExistingSetsInCurrentDisplayOrder(): void
+    {
+        $migration = $this->runMigrationAgainstLegacySets();
+
+        $this->assertSame(
+            [2, 7],
+            DB::table('sets')->orderBy('sort_order')->pluck('id')->all(),
+        );
+        $this->assertSame(
+            [1, 2],
+            DB::table('sets')
+                ->orderBy('sort_order')
+                ->pluck('sort_order')
+                ->all(),
+        );
+
+        $this->expectException(QueryException::class);
+        DB::table('sets')->insert([
+            'id' => 9,
+            'name' => 'Unordered Set',
+            'description' => 'A set without an explicit position',
+            'icon_image_url' => '/assets/unordered.png',
+        ]);
+    }
+
+    public function testRollbackRemovesOrderWithoutDeletingSets(): void
+    {
+        $migration = $this->runMigrationAgainstLegacySets();
+
+        $migration->down();
+
+        $this->assertFalse(Schema::hasColumn('sets', 'sort_order'));
+        $this->assertSame(
+            [2, 7],
+            DB::table('sets')->orderBy('id')->pluck('id')->all(),
+        );
+    }
+
+    private function runMigrationAgainstLegacySets(): object
+    {
+        if (Schema::hasColumn('sets', 'sort_order')) {
+            Schema::table('sets', function (Blueprint $table): void {
+                $table->dropColumn('sort_order');
+            });
+        }
+
+        DB::table('sets')->delete();
+        DB::table('sets')->insert([
+            [
+                'id' => 7,
+                'name' => 'Later Set',
+                'description' => 'Created later',
+                'icon_image_url' => '/assets/later.png',
+            ],
+            [
+                'id' => 2,
+                'name' => 'Earlier Set',
+                'description' => 'Created earlier',
+                'icon_image_url' => '/assets/earlier.png',
+            ],
+        ]);
+
+        $migration = require database_path(self::MIGRATION_PATH);
+        $migration->up();
+
+        return $migration;
+    }
+}