From 27768cd69cfe2a28de89abf88e3c122305ff25e6 Mon Sep 17 00:00:00 2001
From: Shlee <github@shl.ee>
Date: Sat, 29 Aug 2026 22:53:23 +0930
Subject: [PATCH] Create HashtagCollationTest.php

---
 tests/Feature/HashtagCollationTest.php | 108 +++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 tests/Feature/HashtagCollationTest.php

diff --git a/tests/Feature/HashtagCollationTest.php b/tests/Feature/HashtagCollationTest.php
new file mode 100644
index 000000000..bde6b4af4
--- /dev/null
+++ b/tests/Feature/HashtagCollationTest.php
@@ -0,0 +1,108 @@
+<?php
+
+use App\Models\Hashtag;
+use Illuminate\Foundation\Testing\LazilyRefreshDatabase;
+use Illuminate\Support\Facades\Artisan;
+use Illuminate\Support\Facades\DB;
+
+uses(LazilyRefreshDatabase::class);
+
+/*
+|--------------------------------------------------------------------------
+| Hashtag collation fix (PR #6098)
+|--------------------------------------------------------------------------
+|
+| Verifies that the hashtags collation migration runs safely on all drivers
+| and, on MySQL/MariaDB, prevents conflation of distinct hashtags that use
+| characters outside the Basic Multilingual Plane (codepoints >= 0x10000).
+|
+*/
+
+it('migration runs without error regardless of database driver', function () {
+    // The test suite uses sqlite by default. The migration detects the driver
+    // and no-ops gracefully rather than attempting unsupported ALTER syntax.
+    Artisan::call('migrate', [
+        '--path' => 'database/migrations/2025_07_31_164635_change_hashtags_collation.php',
+        '--force' => true,
+    ]);
+
+    // If we reach here without exception the no-op path worked.
+    expect(true)->toBeTrue();
+});
+
+it('migration rollback runs without error regardless of database driver', function () {
+    Artisan::call('migrate', [
+        '--path' => 'database/migrations/2025_07_31_164635_change_hashtags_collation.php',
+        '--force' => true,
+    ]);
+
+    Artisan::call('migrate:rollback', [
+        '--path' => 'database/migrations/2025_07_31_164635_change_hashtags_collation.php',
+        '--force' => true,
+    ]);
+
+    expect(true)->toBeTrue();
+});
+
+it('distinct BMP-outside hashtags do not collide on the unique index', function () {
+    // This test is only meaningful on MySQL/MariaDB where the collation fix matters.
+    if (! in_array(DB::connection()->getDriverName(), ['mysql', 'mariadb'], true)) {
+        $this->markTestSkipped('Collation behavior is MySQL/MariaDB-specific.');
+    }
+
+    // Ensure the migration has been applied.
+    Artisan::call('migrate', [
+        '--path' => 'database/migrations/2025_07_31_164635_change_hashtags_collation.php',
+        '--force' => true,
+    ]);
+
+    // Two distinct 5-character hashtags using characters outside the BMP.
+    // Under the old utf8mb4_unicode_ci collation these were considered equal.
+    $shavian = '𐑖𐑱𐑝𐑾𐑯';     // Shavian script
+    $cuneiform = '𒆳𒆍𒀭𒊏𒆠';   // Cuneiform script
+
+    $tag1 = Hashtag::create(['name' => $shavian, 'slug' => $shavian]);
+    $tag2 = Hashtag::create(['name' => $cuneiform, 'slug' => $cuneiform]);
+
+    // Both must coexist as separate rows with distinct IDs.
+    expect($tag1->id)->not->toBe($tag2->id);
+    expect(Hashtag::where('slug', $shavian)->first()->id)->toBe($tag1->id);
+    expect(Hashtag::where('slug', $cuneiform)->first()->id)->toBe($tag2->id);
+});
+
+it('same-script hashtags with the same slug still correctly deduplicate', function () {
+    // Sanity check: two identical hashtags should NOT create duplicates.
+    if (! in_array(DB::connection()->getDriverName(), ['mysql', 'mariadb'], true)) {
+        $this->markTestSkipped('Collation behavior is MySQL/MariaDB-specific.');
+    }
+
+    Artisan::call('migrate', [
+        '--path' => 'database/migrations/2025_07_31_164635_change_hashtags_collation.php',
+        '--force' => true,
+    ]);
+
+    $tag = Hashtag::firstOrCreate(['slug' => 'hello'], ['name' => 'hello']);
+    $same = Hashtag::firstOrCreate(['slug' => 'hello'], ['name' => 'hello']);
+
+    expect($tag->id)->toBe($same->id);
+    expect(Hashtag::where('slug', 'hello')->count())->toBe(1);
+});
+
+it('case-insensitivity is preserved after collation change', function () {
+    // utf8mb4_unicode_520_ci is still case-insensitive, so #Hello == #hello.
+    if (! in_array(DB::connection()->getDriverName(), ['mysql', 'mariadb'], true)) {
+        $this->markTestSkipped('Collation behavior is MySQL/MariaDB-specific.');
+    }
+
+    Artisan::call('migrate', [
+        '--path' => 'database/migrations/2025_07_31_164635_change_hashtags_collation.php',
+        '--force' => true,
+    ]);
+
+    Hashtag::create(['name' => 'Pixelfed', 'slug' => 'pixelfed']);
+
+    // Case-insensitive lookup should find it with different casing.
+    $found = Hashtag::where('slug', 'PIXELFED')->first();
+    expect($found)->not->toBeNull();
+    expect($found->slug)->toBe('pixelfed');
+});