Assertions in async callbacks will not mark tests as failed

Looking through the tests for NSS I see some that don't appear to actually achieve anything (unless I'm missing something).

Some of them have been marked to skip, which is fair enough.

For example:

https://github.com/solid/node-solid-server/blob/master/test/integration/ldp-test.js#L178
https://github.com/solid/node-solid-server/blob/master/test/integration/ldp-test.js#L199
https://github.com/solid/node-solid-server/blob/master/test/integration/ldp-test.js#L214
https://github.com/solid/node-solid-server/blob/master/test/integration/ldp-test.js#L326 (This one isn't skipped)

If they're in tests like that, there could be a possibility that it's leaked into NSS itself as well.

Beginne damit, die asynchronen Testfälle in test/integration/ldp-test.js in den Zeilen 178, 199, 214 und 326 zu lesen. Prüfe, wie Assertions innerhalb ihrer Callbacks behandelt werden, und sieh dir anschließend den zugehörigen NSS-Testcode auf dasselbe Muster hin an. Als abgeschlossen gilt die Aufgabe, wenn die betroffenen Tests Assertion-Fehler zuverlässig melden, statt sie stillschweigend zu bestehen.