I would suggest making the expectations a bit less "smart". When dealing with tests it is usually a much more pleasant experience to be visually decoding the code under test, and not the test itself. In this instance the amount of functional sugar used occludes the fact that we want to verify that all keys we are scanning are kind_of(String). Can we use a more pedestrian each_pair (or alike) to the same effect?

Sure, I agree the tests should be less "smart"!

Are you suggesting something like this?

result['entries'].each do |entry|
  entry.each do |key, value|
    expect(key).to be_a(String)
  end
end

I couldn't see a simpler way other than that.

Yep that's perfect! If you opt for #each you might want to group the key-value using () though 😉

From what I've seen, each_pair is an alias to each, isn't it?

you might want to group the key-value using () though

I didn't get it. Could you give me an example pls?

Sure! I think some_hash.each do |(key, value)| is required instead of some_hash.each do |key, value| so that the array argument to the block is expanded into two variables. Or you can use each_pair instead

cool! I didn't know about this parenthesis rule for block variables!

Sorry for the long discussion about it, but I found interesting to know how it works and I think it's good to share it with you!

From what I saw, it is not necessary to use the () here. It would be necessary if the hash contained arrays as values and I wanted to access their values like this:

In this case, there are no arrays inside the hashes, and I just want to check their keys, so it makes no difference using ():

And also makes no difference using each or each_with_pair given they are aliases!