public function testGetNextUrl()
 {
     $this->paginator->setCurrentPage(1);
     $this->paginator->setUrlPattern('/example/page(:num)');
     $this->assertEquals('/example/page2', $this->paginator->getNextUrl());
     // Returns null if on the last page.
     $this->paginator->setCurrentPage($this->paginator->getNumPages());
     $this->assertNull($this->paginator->getNextUrl());
 }