public function testToArrayWithNullValue()
 {
     $words = 'plutôt cela';
     $query = 'Batman';
     $hits = null;
     $suggestion = new SearchEngineSuggestion($query, $words, $hits);
     $this->assertEquals(['query' => $query, 'hits' => null, 'suggestion' => $words], $suggestion->toArray());
 }