Psuedo-code for choosing a random student

reference_docs.md

• https://relishapp.com/rspec/rspec-mocks/v/3-0/docs/old-syntax/any-instance#block-implementation-is-passed-the-receiver-as-first-arg
• http://guides.rubyonrails.org/active_record_querying.html#scopes
• http://api.rubyonrails.org/classes/ActionDispatch/Routing/Mapper/Scoping.html#method-i-scope

student.rb

class Student < ActiveRecord::Base

  default_scope ->{ order("id ASC") }
	scope :not_called_on_today, ->{  my_scope_definition_goes_here }

	def self.pick_victim
		# This assumes the not_called_on_today is a named scope, defined elsewhere in the class
		possible_students = Student.not_called_on_today.all
		possible_students.sample # Gives us a random student from the list
	end
end

student_spec.rb

RSpec.describe "Choosing a victim" do
  it 'can return the first valid choice' do
		student_1 = Fabricate(:student)
		Fabricate(:student)
		Fabricate(:student)
		Fabricate(:student, called_on: 1.hour.ago)
    Array.any_instance.stub(:sample) do |array|
      array[0]
    end
		Student.pick_victim.should == student_1
	end

  it 'can return the last valid choice' do
		Fabricate(:student)
		Fabricate(:student)
		student_3 = Fabricate(:student)
		Fabricate(:student, called_on: 1.hour.ago)
    Array.any_instance.stub(:sample) do |array|
      array.last
    end
		Student.pick_victim.should == student_3
	end
end