MongoId creation of embedded models work even if the base _id is an empty string

+ Laravel coding style of '!'

src/Jenssegers/Mongodb/Relations/EmbedsMany.php

@@ -141,7 +141,7 @@ class EmbedsMany extends Relation {
     public function save(Model $model)
     {
         // Insert a new document.
-        if (!$model->exists)
+        if ( ! $model->exists)
         {
             return $this->performInsert($model);
         }
@@ -162,7 +162,7 @@ class EmbedsMany extends Relation {
     protected function performInsert(Model $model)
     {
         // Create a new key.
-        if (!isset($model['_id']))
+        if ( ! isset($model['_id']) or empty($model['_id']))
         {
             $model->setAttribute('_id', new MongoId);
         }

tests/RelationsTest.php

@@ -341,12 +341,18 @@ class RelationsTest extends PHPUnit_Framework_TestCase {
 
     public function testEmbedsManyCreate()
     {
-        $user = User::create(array('name' => 'John Doe'));
-        $user->addresses()->create(array('city' => 'Bruxelles'));
+        $user = User::create(array());
+        $address = $user->addresses()->create(array('city' => 'Bruxelles'));
+        $this->assertInstanceOf('Address', $address);
+        $this->assertInstanceOf('MongoID', $address->_id);
         $this->assertEquals(array('Bruxelles'), $user->addresses->lists('city'));
 
         $freshUser = User::find($user->id);
         $this->assertEquals(array('Bruxelles'), $freshUser->addresses->lists('city'));
+
+        $user = User::create(array());
+        $address = $user->addresses()->create(array('_id' => '', 'city' => 'Bruxelles'));
+        $this->assertInstanceOf('MongoID', $address->_id);
     }
 
     public function testEmbedsManyDestroy()