i think getNodename did not always check if what you pass to it is actually an absolute path or even has any slashes in it, leading to weird results when you happened to give it something strange like an empty string. the test is asserting that if we do getNodeName and there is no id defined, we get back false.

        $this->assertEquals(false, $this->extension->getNodeName($document));

i propose to respect our interface, we should `return false` if $path is not good (never null or '')

i am fixing the other test failure on #122 directly, that one is related to the change.