ruby-on-rails - 测试 Rails 助手是否呈现部分

Question

给定以下辅助方法，我如何使用 rspec 正确测试它？

  def datatable(rows = [], headers = [])
    render 'shared/datatable', { :rows => rows, :headers => headers }
  end

  def table(headers = [], data = [])
    render 'shared/table', headers: headers, data: data
  end

我尝试了以下方法，但出现错误:can't convert nil into String

describe 'datatable' do
  it 'renders the datatable partial' do
    rows = []
    headers = []
    helper.should_receive('render').with(any_args)
    datatable(rows, headers)
  end
end

Rspec 输出

Failures:

  1) ApplicationHelper datatable renders the datatable partial
     Failure/Error: datatable(rows, headers)
     TypeError:
       can't convert nil into String
     # ./app/helpers/application_helper.rb:26:in `datatable'
     # ./spec/helpers/application_helper_spec.rb:45:in `block (3 levels) in <top (required)>'

./app/helpers/application_helper.rb:26

render 'shared/datatable', { :rows => rows, :headers => headers }

views/shared/_datatable.html.haml

= table headers, rows

views/shared/_table.html.haml

%table.table.dataTable
  %thead
    %tr
      - headers.each do |header|
        %th= header
  %tbody
    - data.each do |columns|
      %tr
        - columns.each do |column|
          %td= column

Answer 1

如果您只想测试您的助手是否使用正确的参数调用了正确的部分，您可以执行以下操作:

describe ApplicationHelper do

  let(:helpers) { ApplicationController.helpers }

  it 'renders the datatable partial' do
    rows    = double('rows')
    headers = double('headers')

    helper.should_receive(:render).with('shared/datatable', headers: headers, rows: rows)

    helper.datatable(rows, headers)
  end

end

请注意，这不会调用您的部分中的实际代码。