Rails / Tests with rspec : Is there a way to test includes in Rails queries

Is it possible to test includes in Rails query (Rails 5 / tests with rspec-rails) ?

I can see includes are ok in log files, but I would like to write a test for this. I looked in docs but I'm not able to find any solution.

My query :

def concepts_by_type(type_c)
  includes(var_concepts: [{domain: [:vals, :syms]}, :variable]).where(concept_types: {label: type_c}).order('ancestry ASC')
end