Use rails built in send_file method

[the-undefined]

In Rails 5.1.3 the csv export was not outputting the table contents, it was trying to render the layout file but in a CSV format:

The proposed fix is to use the Rails send_file method over send_file_rails2 which is defined in wice grid itself (and called by export_grid_if_requested).

I'm not too sure what it would take to get the send_file_rails2 method updated to work alongside the rails one: https://github.com/rails/rails/blob/375a4143cf5caeb6159b338be824903edfd62836/actionpack/lib/action_controller/metal/data_streaming.rb#L67 or what specifically was breaking / missing from the send_file_rails2 if we do need to keep it around.

This change resulted in the CSV export function working as expected. It will be interesting to see if the tests are still passing with the send_file method once the testbed has been ported over. If we can adopt the rails method then a good chunk of this controller code (lib/wice/wice_grid_controller.rb) could be deleted.

[patricklindsay]

Thanks for the contribution @the-undefined

The test suite has now been ported over so should be able to check that out. I don't want to merge things until we have a passing build.

[the-undefined]

I have found that the CSV spec needs fleshing out a bit:

# spec/features/csv_export_request_spec.rb

# encoding: utf-8
require 'acceptance_helper'

describe 'CSV export WiceGrid', type: :request, js: true do
  before :each do
    visit '/csv_export'
  end

  it 'should export csv' do
    # no idea how to test these

    # find(:css, 'button.wg-external-csv-export-button').click

    select 'Urgent', from: 'g1_f_priority_id'

    # find(:css, 'button.div.clickable.export-to-csv-button').click
  end
end

So I'll update the specs for CSV export as part of this PR.

[JasonBarnabe]

send_file_rails2 is fixed (with tests added) in #4, but removing as suggested here may be the better solution.