Fixes issue where translations other than default were not saved.

Fixes #4726

src/Model/Behavior/TranslateBehavior.php

@@ -173,6 +173,7 @@ class TranslateBehavior extends Behavior {
 		$options['associated'] = $newOptions + $options['associated'];
 
 		$this->_bundleTranslatedFields($entity);
+		$bundled = $entity->get('_i18n') ?: [];
 
 		if ($locale === $this->config('defaultLocale')) {
 			return;
@@ -204,7 +205,7 @@ class TranslateBehavior extends Behavior {
 			]);
 		}
 
-		$entity->set('_i18n', array_values($modified + $new));
+		$entity->set('_i18n', array_merge($bundled, array_values($modified + $new)));
 		$entity->set('_locale', $locale, ['setter' => false]);
 		$entity->dirty('_locale', false);
 

tests/TestCase/Model/Behavior/TranslateBehaviorTest.php

@@ -18,11 +18,20 @@ use Cake\Collection\Collection;
 use Cake\Event\Event;
 use Cake\I18n\I18n;
 use Cake\Model\Behavior\TranslateBehavior;
+use Cake\Model\Behavior\Translate\TranslateTrait;
 use Cake\ORM\Entity;
 use Cake\ORM\TableRegistry;
 use Cake\TestSuite\TestCase;
 
 /**
+ * Stub entity class
+ */
+class Article extends Entity {
+
+	use TranslateTrait;
+}
+
+/**
  * Translate behavior test case
  */
 class TranslateBehaviorTest extends TestCase {
@@ -758,4 +767,31 @@ class TranslateBehaviorTest extends TestCase {
 		$this->assertNotEmpty($article->get('_translations'));
 	}
 
+/**
+ * Tests that multiple translations saved when having a default locale
+ * are correclty saved
+ *
+ * @return void
+ */
+	public function testSavingWithNonDefaultLocale() {
+		$table = TableRegistry::get('Articles');
+		$table->addBehavior('Translate', ['fields' => ['title', 'body']]);
+		$table->entityClass(__NAMESPACE__ . '\Article');
+		I18n::locale('fra');
+		$translations = [
+			'fra' => ['title' => 'Un article'],
+			'spa' => ['title' => 'Un artículo']
+		];
+
+		$article = $table->get(1);
+		foreach ($translations as $lang => $data) {
+			$article->translation($lang)->set($data, ['guard' => false]);
+		}
+
+		$table->save($article);
+		$article = $table->find('translations')->where(['Articles.id' => 1])->first();
+		$this->assertEquals('Un article', $article->translation('fra')->title);
+		$this->assertEquals('Un artículo', $article->translation('spa')->title);
+	}
+
 }