Table based testing

table_based.rb

# Account = Struct.new(:id, :last_active)

describe 'pruning expired accounts' do
  let(:f) {
    # an account factory
    lambda do |id, last_active=Date.today|
      Account.new(id, last_active)
    end
  }
  
  it 'prunes accounts based on last_active and id' do
    cases = [
     { 
       input: [f.(1), f.(2), f.(3)],
       output: [f.(1), f.(2), f.(3)],
       message: 'all three are valid'
     }, {
       input: [f.(1), f.(2), f.(3, Date.today-30)],
       output: [f.(1), f.(2)],
       message: 'third is expired'
     }, {
       input: [f.(1), f.(2, Date.today-30), f.(3, Date.today-30)],
       output: [f.(1)],
       message: 'second and third are expired'
     }, {
       input: [f.(-1), f.(2), f.(3)],
       output: [f.(2), f.(3)],
       message: 'first has invalid id'
     }
    ]
    
    # ... 
    
    cases.each do |c|
      expect(AccountPruner.prune(*c[:input])).to eq(c[:output]), c[:message]
    end
  end
end