Further refactorings to PHPUnit namespaces

Author: peterrehm

Tests/CrawlerTest.php

@@ -886,6 +886,8 @@ public function testChildren()
             $crawler = new Crawler('<p></p>');
             $crawler->filter('p')->children();
             $this->assertTrue(true, '->children() does not trigger a notice if the node has no children');
+        } catch (\PHPUnit\Framework\Error\Notice $e) {
+            $this->fail('->children() does not trigger a notice if the node has no children');
         } catch (\PHPUnit_Framework_Error_Notice $e) {
             $this->fail('->children() does not trigger a notice if the node has no children');
         }