feat: add locale-specific translation functionality with tests

Author: hamidgh83

src/Traits/TranslatableTrait.php

@@ -11,6 +11,8 @@ trait TranslatableTrait
 {
     private $cachedTranslationModels;
 
+    private $locale;
+
     public function __get($key)
     {
         if ($this->isRelation($key)) {
@@ -37,6 +39,23 @@ public function translations(): MorphMany
         return $this->morphMany(Translation::class, 'translatable');
     }
 
+    /**
+     * Sets the locale for the current model instance.
+     *
+     * This method allows you to specify a locale for the model, which will be used when retrieving
+     * translated attributes.
+     *
+     * @param string $locale the locale to set for the model
+     *
+     * @return $this the current model instance, for method chaining
+     */
+    public function withLocale(string $locale): self
+    {
+        $this->locale = $locale;
+
+        return $this;
+    }
+
     /**
      * Retrieves the list of attributes that are translatable for the current model.
      *
@@ -54,6 +73,15 @@ protected function getTranslatableAttributes()
         return null;
     }
 
+    private function popTranslationLocale(): string
+    {
+        $locale = $this->locale ?? app()->getLocale();
+
+        $this->locale = null;   // reset the current locale
+
+        return $locale;
+    }
+
     /**
      * Retrieves the translation for the given attribute key, if the attribute is translatable.
      *
@@ -103,7 +131,7 @@ private function getCachedTranslations(): Collection
         }
 
         // If not cached or not found for current locale, fetch and cache translations
-        return $this->cachedTranslationModels = $this->fetchAndCacheTranslations(app()->getLocale());
+        return $this->cachedTranslationModels = $this->fetchTranslations($this->popTranslationLocale());
     }
 
     /**
@@ -113,19 +141,19 @@ private function getCachedTranslations(): Collection
      */
     private function hasTranslationsForCurrentLocale(): bool
     {
-        $locale = app()->getLocale();
+        $locale = $this->popTranslationLocale();
 
         return null !== $this->cachedTranslationModels->firstWhere('locale', $locale);
     }
 
     /**
-     * Fetches and caches the translation models for the given locale.
+     * Fetches the translation models for the given locale.
      *
      * @param string $locale the locale to fetch translations for
      *
      * @return Collection the collection of translation models
      */
-    private function fetchAndCacheTranslations(string $locale): Collection
+    private function fetchTranslations(string $locale): Collection
     {
         return $this->translation()->locale($locale)->get();
     }

tests/TranslationModelTest.php

@@ -9,11 +9,6 @@
 use Jetcod\Laravel\Translation\Test\Stubs\Post;
 use Orchestra\Testbench\TestCase as PHPUnitTestCase;
 
-/**
- * @internal
- *
- * @coversNothing
- */
 class TranslationModelTest extends PHPUnitTestCase
 {
     use RefreshDatabase;
@@ -81,7 +76,7 @@ public function testItReturnsOriginalTextWhenNoTranslationIsAvailable()
 
     public function testItTranslatesOnlyTranslatableAttributes()
     {
-        $post = new class() extends Post {
+        $post = new class extends Post {
             protected const TRANSLATABLE_ATTRIBUTES = 'name';
         };
         $post->id   = 1;
@@ -129,7 +124,7 @@ public function testItTranslatesAttributesImmediatelyAfterSwitchingLocale()
 
     public function testItTranslatesAllAttributesIfNoTranslatableAttributesAreDefined()
     {
-        $post = new class() extends Post {
+        $post = new class extends Post {
             protected function getTranslatableAttributes()
             {
                 return null;
@@ -190,6 +185,60 @@ public function testItReturnsTranslationsCollection()
         }
     }
 
+    public function testItCanGetTranslationForDefinedLocale()
+    {
+        $post       = new Post();
+        $post->id   = 1;
+        $post->name = 'original text goes here';
+
+        $post->translation()->saveMany([
+            new Translation([
+                'locale' => 'fr_FR',
+                'key'    => 'name',
+                'value'  => 'un texte va ici',
+            ]),
+        ]);
+
+        $this->assertEquals('un texte va ici', $post->withLocale('fr_FR')->name);
+    }
+
+    public function testItResetsDefinedLocaleForEachRequest()
+    {
+        $post       = new Post();
+        $post->id   = 1;
+        $post->name = 'original text goes here';
+
+        $post->translation()->saveMany([
+            new Translation([
+                'locale' => 'fr_FR',
+                'key'    => 'name',
+                'value'  => 'un texte va ici',
+            ]),
+        ]);
+
+        $this->assertEquals('un texte va ici', $post->withLocale('fr_FR')->name);
+        $this->assertEquals('original text goes here', $post->name);
+    }
+
+    public function testChangingApplicationLocaleDoesNotAffectTranslationIfLocaleIsSet()
+    {
+        $post       = new Post();
+        $post->id   = 1;
+        $post->name = 'original text goes here';
+
+        $post->translation()->saveMany([
+            new Translation([
+                'locale' => 'fr_FR',
+                'key'    => 'name',
+                'value'  => 'un texte va ici',
+            ]),
+        ]);
+
+        app()->setLocale('ja_JP');
+        $this->assertEquals('un texte va ici', $post->withLocale('fr_FR')->name);
+        $this->assertEquals('ja_JP', app()->getLocale());
+    }
+
     protected function getPackageProviders($app)
     {
         return [TranslationServiceProvider::class];