        it 'should write the public key to disk if its the first time its been seen' do
          @plugin.stubs(:lookup_config_option).with('learn_public_keys').returns('1')
          @plugin.stubs(:lookup_config_option).with('publickey_dir').returns('ssh/pkd')
          File.stubs(:directory?).with('ssh/pkd').returns(true)
          File.stubs(:exists?).with('ssh/pkd/rspec_pub.pem').returns(false)
          file = mock
          File.expects(:open).with('ssh/pkd/rspec_pub.pem', 'w').yields(file)
          file.expects(:puts).with('ssh-rsa abcd')
          @plugin.send(:write_key_to_disk, 'ssh-rsa abcd', 'rspec')
        end
The product receives input or data, but it does
        not validate or incorrectly validates that the input has the
        properties that are required to process the data safely and
        correctly.