Why do I get Active record relation instead of Array in rspec?

I'm running tests on Post:

expect(subject.query).to eq [previous_post, post, future_comment]

But I get this error :

expected: [#<Post id: 3, body: "Sed quis aut harum. Asperiores ad commodi tempore ...", ...>]


got: #<ActiveRecord::Relation [#<Post id: 3, body: "Sed quis aut harum. Asperiores a.....>]>

It expected an array but get an active record object. How can I resolve that ?

This is the code i'm testing :

      def query
        scope = Post
                .where(user_id: user.id)
                .my_scope
                .my_other_scope
                .includes(:body)

        scope = case @options[:order_by]
                when "older"
                  order_by_older(scope)
                when "most_discussed"
                  order_by_most_discussed(scope)
                else
                  order_by_older(scope)
                end

        scope
      end