Action: Negative testing - Is there a "Not Contains" action?

[MrMPorter]

I am looking for a way to test that a string is not in the Response Body.
For example, I have a route that has options for returning a full set of fields or a partial set of fields.
I can easily test the full set of fields by using Contains.
"ResponseBody Contains 'UnitNumber':"
When I use the partial set of fields I want to test that one of the full fields is not in the Response Body.
"ResponseBody NotContains 'UnitNumber':"
Suggestions?

[rangav]

Thanks @MrMPorter for the feedback. It's a good suggestion.

can you please create a new feature request for this