File.exists? type testing

Type.rb

Puppet::Type.newtype(:domain) do
  @doc = "Manage Glassfish domains"

  ensurable

...

  newparam(:passwordfile) do
    desc "The file containing the password for the user."

    validate do |value|
      unless File.exists? value
        raise ArgumentError, "%s does not exist" % value
      end
    end
  end
...
end

type_spec.rb

require 'spec_helper'

describe Puppet::Type.type(:domain) do

  before :each do
    described_class.stubs(:defaultprovider).returns providerclass
  end

  let :providerclass do
    described_class.provide(:fake_domain_provider) { mk_resource_methods }
  end

...
    describe "for passwordfile" do
      it "should support a valid file path" do
        #File.stubs(:exists?).with('/tmp/asadmin.pass').returns(:true)
        File.expects(:exists?).with('/tmp/asadmin.pass').returns(true).once
        described_class.new(:domainname => 'domain', :passwordfile => '/tmp/asadmin.pass')[:passwordfile].should == '/tmp/asadmin.pass'
      end

      it "should fail an invalid file path" do
        #File.stubs(:exists?).with('/tmp/nonexistent').returns(:false)
        File.expects(:exists?).with('/tmp/nonexistent').returns(false).once
        expect { described_class.new(:domainname => 'domain', :passwordfile => '/tmp/nonexistent') }.to raise_error(Puppet::Error, /does not exist/)
      end
    end
...
end