public function testViewGuestBookWithEntries()
 {
     $GuestBook = new GuestBook();
     $GuestBook->add('Bob', 'Hi, I\'m Bob.');
     $GuestBook->add('Tom', 'Hi, I\'m Tom.');
     $entries = $GuestBook->viewAll();
     $this->assertGreaterThan(0, count($entries));
     $this->assertTrue(is_array($entries));
     foreach ($entries as $entry) {
         $this->assertTrue(is_array($entry));
         $this->assertArrayHasKey('name', $entry);
         $this->assertArrayHasKey('message', $entry);
     }
 }