Question

I have an Array/Enumerable where each entity is a Hash. Using RSpec what is the most idiomatic way to test for “none of the entries in the enumerable should have a key called 'body'“?

I can do something like:

array.none? {|thing| thing.key? 'body'}.should be_true

or

array.should be_none {|thing| thing.key? 'body'}

…but there must be a more RSpec-way of doing this, correct?

I can’t seem to find an appropriate built-in matcher. Is the answer a custom matcher?

Answer 1

I would use
responses.should be_none { |response| response.key? 'body' }

Between the two you gave. This would be slightly more helpful with an error like

“Expected none? to return true”

where as your first example would say something like

“expected False:false class to be true”

The third option I can see would be something like

 keys = responses.map { |response| response.keys }.flatten.uniq
 keys.should_not include "body"

This would give an error like

expected [“foo”, “bar”, “body”] not to include “body”

Other than that, looking at https://www.relishapp.com/rspec/rspec-expectations/v/2-11/docs/built-in-matchers/satisfy-matcher

you could try

responses.should satisfy { |response| not response.keys.include? "body" }