test 'should display correct validation message a consumption' do
    type 'OX169BX', into: POSTCODE_FIELD
    click FIND_ADDRESS
    choose FIRST_ADDRESS
    choose USAGE_KNOWN

    type '', return: true, into: CONSUMPTION_TOTAL_FIELD
    blur

    assert_equal 'Please enter your usage in kwh', error_message_for_field(find(CONSUMPTION_TOTAL_FIELD))
  end