Github user MikeThomsen commented on the issue:
https://github.com/apache/nifi/pull/2101
@mans2singh This works in the unit test per @mattyb149 's point:
```
runner.assertValid();
runner.setProperty(PutInfluxDB.PASSWORD, "");
runner.assertNotValid();
```
And that's with `NON_EMPTY_VALIDATOR` being used.---
