A Case For RPSPEC Custom Matcher.md

This gist contains code for blog post A Case For RPSPEC Custom Matcher

• spec1.rb : RSPEC validating that implemented_rule includes expected_rule
• spec1-error.rb : RSPEC falsifying that implemented_rule includes expected_rule
• spec2.rb : RSPEC validating that at least of of the rules in array of implemented_rules include expected_rule, defines a new matcher include_rule for validation
• spec2-error.rb : RSPEC falsifying new custom matcher include_rule

spec1-error.rb

implemented_rule =    
{
     :to_port => -1,
     :from_port => -1,
     :ip_protocol => "icmp",
     :ip_ranges => [ { :cidr_ip => "10.0.0.0/16" } ]
 }

expected_rule = {
  :to_port => -1,
  :ip_protocol => "icmp",
  :ip_ranges => [ { :cidr_ip => "0.0.0.0/0" } ]

}

describe "implemented_rule" do
   it "#includes expected_rule" do
      expect( implemented_rule ).to include( expected_rule )
   end
end

spec1.rb

implemented_rule =
{
     :to_port => -1,
     :from_port => -1,
     :ip_protocol => "icmp",
     :ip_ranges => [ { :cidr_ip => "0.0.0.0/0" } ]
 }

expected_rule = {
  :to_port => -1,
  :ip_protocol => "icmp",
  :ip_ranges => [ { :cidr_ip => "0.0.0.0/0" } ]

}


describe "implemented_rule" do
   it "#includes expected_rule" do
      expect( implemented_rule ).to include( expected_rule )
   end
end

spec2-error.rb

implemented_rules = [
     {
          :to_port => -1,
          :from_port => -1,
          :ip_protocol => "icmp",
          :ip_ranges => [ { :cidr_ip => "10.0.0.0/16" } ]
      },
     {
          :to_port => 80,
          :from_port => 80,
          :ip_protocol => "tcp",
          :ip_ranges => [ { :cidr_ip => "10.0.0.0/16" } ]
      },
     {
          :to_port => 443,
          :from_port => 443,
          :ip_protocol => "tcp",
          :ip_ranges => [ { :cidr_ip => "10.0.0.0/16" } ]
      }
]

expected_rule = {
  :to_port => -1,
  :ip_protocol => "icmp",
  :ip_ranges => [ { :cidr_ip => "0.0.0.0/0" } ]

}

RSpec::Matchers.define :include_rule do |expected|

  match do |actual_rules|

    result = false

    actual_rules.each do |rule|
      begin 
        result = expect( rule ).to include( expected )
        break if result
      rescue Exception => e
      end
    end
    return result
  end

  failure_message do |actual_rules|
    <<-EOS

    rule 

    #{expected}

     was not included in actual rules:

     #{actual_rules.join( "\n" )}
    EOS
  end

end
describe "implemented_rules" do
   it "#includes expected_rule" do
      expect( implemented_rules ).to include_rule( expected_rule )
   end
end

spec2.rb

implemented_rules = [
     {
          :to_port => -1,
          :from_port => -1,
          :ip_protocol => "icmp",
          :ip_ranges => [ { :cidr_ip => "0.0.0.0/0" } ]
      },
     {
          :to_port => 80,
          :from_port => 80,
          :ip_protocol => "tcp",
          :ip_ranges => [ { :cidr_ip => "10.0.0.0/16" } ]
      },
     {
          :to_port => 443,
          :from_port => 443,
          :ip_protocol => "tcp",
          :ip_ranges => [ { :cidr_ip => "10.0.0.0/16" } ]
      }
]

expected_rule = {
  :to_port => -1,
  :ip_protocol => "icmp",
  :ip_ranges => [ { :cidr_ip => "0.0.0.0/0" } ]

}

RSpec::Matchers.define :include_rule do |expected|

  match do |actual_rules|

    result = false

    actual_rules.each do |rule|
      begin 
        result = expect( rule ).to include( expected )
        break if result
      rescue Exception => e
      end
    end
    return result
  end

  failure_message do |actual_rules|
    <<-EOS

    rule 

    #{expected}

     was not included in actual rules:

     #{actual_rules.join( "\n" )}
    EOS
  end

end
describe "implemented_rules" do
   it "#includes expected_rule" do
      expect( implemented_rules ).to include_rule( expected_rule )
   end
end