Contents

require 'spec_helper'
require 'method_decorators/decorators/precondition'

describe Precondition do
  let(:receiver) { double(:receiver) }
  let(:method) { double(:method, :call => :secret, :receiver => receiver) }
  let(:block) { proc { |arg| true } }
  subject { Precondition.new(&block) }

  describe "#call" do
    it "raises when the precondition fails" do
      subject.stub(:passes?){ false }
      expect{ subject.call(method) }.to raise_error(ArgumentError)
    end

    it "executes the method when authorization succeeds" do
      subject.stub(:passes?){ true }
      subject.call(method).should == :secret
    end
  end

  describe "acceptance" do
    let(:klass) do
      Class.new Base do
        def initialize(x)
          @x = x
        end

        +Precondition.new{ |a| a + @x < 10 }
        def multiply(a)
	  a * @x
        end
      end
    end
    subject { klass.new(3) }

    it "calls the method if the precondition passes" do
      subject.multiply(2).should == 6
    end

    it "raises if the precondition passes" do
      expect{ subject.multiply(8) }.to raise_error(ArgumentError)
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
method_decorators-0.9.1	spec/decorators/precondition_spec.rb