function testWidthAndHeightGetters()
 {
     $is = new ImageServing(null, 200, 100);
     $this->assertEquals(200, $is->getRequestedWidth());
     $this->assertEquals(100, $is->getRequestedHeight());
     $is = new ImageServing(null, 300, ['w' => 2, 'h' => 1]);
     $this->assertEquals(300, $is->getRequestedWidth());
     $this->assertEquals(150, $is->getRequestedHeight());
 }