Monitoring SQL assertions and other type

assert_forty_two.rb

class AssertFortyTwo
  include SystemStateAssertion
  describe "the Answer to the Ultimate Question of Life, the Universe, and Everything to be 42"
  expect 42
  def actual
    2
  end
end

assert_no_contact_in_five9_and_in_salesforce.rb

class AssertNoContactInFive9AndInSalesforce
  include SystemStateAssertion
  describe "the number of contacts both in Five9 and in Salesforce to be 0"
  expect 0

  def actual
    @actual ||= Contact.where(:vcc_name => "five9").where("sf_contact_id IS NOT NULL").count
  end
end

assert_there_are_lead_statuses_today.rb

class AssertThereAreLeadStatusesToday
  include SystemStateAssertion
  describe "the number of lead statuses so far today to be greater than 0"
  expect { |value| value.to_i > 0 }
  query  { "select count(ls.id) from lead_statuses ls where ls.created_at > '#{Time.now.to_s(:db)}'" }
end

example.rb

errors = SystemStateAssertion.verify_all
errors.compact!
puts "#{errors.length} error(s)"
errors.each { |error| puts "  - #{error}" }

# => 3 error(s)
# =>   - Expected the Answer to the Ultimate Question of Life, the Universe, and Everything to be 42, but it is 2.
# =>   - Expected the number of contacts both in Five9 and in Salesforce to be 0, but it is 10.
# =>   - Expected the number of lead statuses so far today to be greater than 0, but it is 0.

system_state_assertion.rb

module SystemStateAssertion
  def self.all
    @all ||= []
  end

  def self.included(assertion_klass)
    self.all << assertion_klass
    assertion_klass.extend(ClassMethods)
  end

  def self.verify_all
    all.map { |assertion_klass| assertion_klass.new.verify }
  end

  module ClassMethods
    attr_reader :label, :expectation, :get_sql
    def describe(label)
      @label = label
    end

    def expect(value = nil, &expectation)
      @expectation = expectation || Proc.new { |actual| actual == value }
    end

    def query(&get_sql)
      @get_sql = get_sql
    end
  end

  def message
    "Expected #{self.class.label}, but it is #{actual}."
  end

  def verify
    message unless self.class.expectation.call(actual)
  end

  def actual
    return @actual if instance_variable_defined?(:@actual)
    query = self.class.get_sql.call
    result = ActiveRecord::Base.connection.execute(query)
    @actual = result.fetch_row.first
  end
end