Rspec - archives array to match tested array - ruby-on-rails

Question

I'm having this class method on my Post model for getting archives
def self.archives
Post.unscoped.select("YEAR(created_at) AS year, MONTHNAME(created_at) AS month, COUNT(id) AS total")
.group("year, month, MONTH(created_at)")
.order("year DESC, MONTH(created_at) DESC")
end
This is the test I have wrote for my method
context '.archives' do
first = FactoryGirl.create(:post, published_at: Time.zone.now)
second = FactoryGirl.create(:post, published_at: 1.month.ago)
it 'returns articles archived' do
archives = Post.archives()
expect(
[{
year: first.published_at.strftime("%Y"),
month: first.published_at.strftime("%B"),
published: 1
},
{
year: second.published_at.strftime("%Y"),
month: second.published_at.strftime("%B"),
published: 1
}]
).to match_array(archives)
end
end
However I get the following error
expected collection contained: [#<Post id: nil>, #<Post id: nil>]
actual collection contained: [{:year=>"2017", :month=>"October", :published=>1}, {:year=>"2017", :month=>"September", :total=>1}]
the missing elements were: [#<Post id: nil>, #<Post id: nil>]
the extra elements were: [{:year=>"2017", :month=>"October", :total=>1}, {:year=>"2017", :month=>"September", :total=>1}]
So although I have created 2 factories, the archives array is empty. What am I doing wrong?

Answer 1

Rspec standard is to use the let syntax for defining variables within a context or describe block. The test should look something like this:
describe '.archives' do
let!(:first) { FactoryGirl.create(:post, published_at: Time.zone.now) }
let!(:second) { FactoryGirl.create(:post, published_at: 1.month.ago) }
it 'returns year, month, and total for articles archived' do
actual_attributes = Post.archives.map { |post| [post.year, post.month, post.total] }
expected_total = 1 # I don't know why the query is returning 1 for total, but including this for completeness
expected_attributes = [first, second].map { |post| [post.created_at.year, post.created_at.strftime("%B"), expected_total] }
expect(actual_attributes).to match_array(expected_attributes)
end
end
The issue here is that you are comparing records pulled with only a few attributes (the result of your SQL query) with fully-formed records (created by your test). This test pulls the applicable attributes from both groups and compares them.

Answer 2

Actual array is not empty, it's an array of two Post instances with ids unset (because Select in .archives method doesn't contain id field).
You could compare expected hashes not with archives, but with smth like that:
actual = Post.archives().map do |post|
{ year: post["year"].to_s, month: post["month"], published: post["total"] }
end
expected = [{
year: first.published_at.strftime("%Y").to_s,
month: first.published_at.strftime("%B"),
published: 1
},
{
year: second.published_at.strftime("%Y").to_s,
month: second.published_at.strftime("%B"),
published: 1
}]
expect(actual).to match_array(expected)