public function testShouldValidateSignature()
 {
     $middleware = new ImageResize(array("secret" => "s11kr3t"));
     $signature = ImageResize::signature(array("size" => "100x200", "secret" => "s11kr3t"));
     $this->assertFalse($middleware->validSignature());
     $this->assertTrue($middleware->validSignature(array("signature" => $signature, "size" => "100x200")));
 }