has_only: enforce a fixed sets of JSON object properties

[derek-watson]

I sometimes need to guarantee nothing gets accidentally added to a JSON response. I can't predict what might get accidentally added with has_not, so I've added a has_only method, which will cause any properties that have not been tested with has to throw an exception.

This applies to the object you add the call to, as well as any nested objects.

assert_json '[{"id":1, "key":"test", "name":"test"}, {"id":2, "key":"test", "name":"test"}, {"id":3, "key":"test", "name":"test"}]' do
  has_only
  item 0 do
    has :id, 1
    has :key, 'test'
    has :name, 'test'
  end
  item 1 do
    has 'id', 2
    has 'key', 'test'
  end
end

# Failure: element 1 has unexpected keys: name

[alto]

That's a very cool feature!

[alto]

I released version 0.3.0 including that feature. 👍

[GBH]

👍