Prevent different records with matching IDs from falsely passing tests

approach_01_random_ids.rb

# put this inside spec/support/random_ids.rb

# NOTE: this works, but will break tests whee something like Article.last is used
# a more clever approach is used in 02 below

# Some tests may pass when they should have failed
# due to Rails using sequential ids. This allows us
# to fix that by having random ids.
class ActiveRecord::Base
  before_create :generate_random_id

  private 

  def generate_random_id
    return if self.id
    begin
      # assuming 4 byte postgresql range
      self.id ||= SecureRandom.random_number(2147483647)
    end while self.class.where(id: self.id).exists?
  end 

end

approach_02_namespaced_sequences.rb

# this is the ideal approach, if you're using PostgreSQL
# namespacing each sequence so they don't overlap

RSpec.configure do |config|
  config.before :suite do
    # assuming each record will have maximum of 99 999 records created,
    # in a single test suite, which should be more than enough
    namespace_size = 100_000
    # select sequences so we can set their start
    sequences = ActiveRecord::Base.connection.execute("SELECT c.relname FROM pg_class c WHERE c.relkind = 'S'")
    sequences.each_with_index { |result, i|
      sequence = result['relname']
      start = namespace_size * (i + 1)
      # start each sequence namespaced
      ActiveRecord::Base.connection.execute("SELECT setval('#{sequence}', #{start})")
    }
  end
end

Nice one @hakunin ! 🚀