Ouzo\ContentType::set PHP Method

    public static function set($contentType)
    {
        self::$contentType = $contentType;
    }

 /**
  * @test
  */
 public function shouldSetContentType()
 {
     //given
     $_SERVER['CONTENT_TYPE'] = 'application/json';
     //when
     ContentType::set('text/plain');
     //then
     $this->assertEquals('text/plain', ContentType::value());
 }