Ability to expect a parameter to not exist

[melcher]

Unsure if this is super useful, but i could see wanting to ensure that a parameter is not sent up, but not wanting to specify every parameter with a withExactly. Could be something like ".without('foo')".

expectation = resource.expect('POST')
expectation.without('foo')
// Would fail with POST /patients  {foo: undefined, bar: 'anything, even foo', bar2: 'foo'}
// Would fail with POST /patients  {foo: 'ok', bar: 'no'}
// Would succeed with POST /patients  {bar: 'anything'}
// Would succeed with POST /patients  {}