Fix UTF-8 encoding and decoding with attributes

Closes #698

Author: stevebauman

src/Models/Concerns/HasAttributes.php

@@ -220,7 +220,7 @@ protected function encodeValue(string $value): string
      */
     protected function decodeValue(string $value): string
     {
-        if (MbString::isLoaded() && MbString::isUtf8($value)) {
+        if (MbString::isLoaded() && ! MbString::isUtf8($value)) {
             return mb_convert_encoding($value, 'UTF-8', 'ISO-8859-1');
         }
 

tests/Unit/Models/ModelSerializationTest.php

@@ -18,6 +18,7 @@ public function testModelWithTimestampsCanBeSerializedAndEncoded()
         $lastlogon = (new Timestamp('windows-int'))->fromDateTime(new DateTime());
 
         $model = (new User())->setRawAttributes([
+            'cn' => 'René',
             'whenchanged' => [(string) $whenchanged],
             'lastlogon' => [(string) $lastlogon],
         ]);
@@ -32,6 +33,8 @@ public function testModelWithTimestampsCanBeSerializedAndEncoded()
 
         $this->assertTrue($model->is($unserializedAndUnencoded));
 
+        $this->assertEquals($model->getOriginal()['cn'], $unserializedAndUnencoded->getOriginal()['cn']);
+
         $this->assertEquals($model->getOriginal()['lastlogon'], $unserializedAndUnencoded->getOriginal()['lastlogon']);
         $this->assertEquals($model->getOriginal()['whenchanged'], $unserializedAndUnencoded->getOriginal()['whenchanged']);