Why can't the _property view call the search_params helper?

app-controllers-application_controller.rb

class ApplicationController < ActionController::Base

  helper_method :client_state     # line 51
  def client_state
    @client_state ||= ClientState.new(request, cookies)
  end

  helper_method :search_params    # line 56
  def search_params
    base_params = { pu: client_state.property_unit, lu: client_state.land_unit }
    @search_params ||= Search::Params.new(base_params.merge(params))
  end

  # (just demonstrating that a bunch of controllers need to call search_params as well)
  def validate_search_params
    if search_params.redirect_needed
      redirect_to request.path + '?' + search_params.query_string
    else
      yield if block_given?
    end
  end
  
  ...
end

app-helpers-search_helper.rb

module SearchHelper
  
  ...

  def preferred_readable_unit type   # line 152
    uom = preferred_unit(type)
    readable_unit(uom)
  end

  def format_uom title, value, uom, type, format="one_line"    # line 157
    return if !good_value?(value)

    pref = preferred_unit(type)
    html = display_units(value, nil, uom, nil, pref)

    render_propdata title, html, format
  end

  def format_property_size property, format  # line 166
    if good_value?(property.lot_size)
      pref = preferred_readable_unit(:land)
      html = display_units(property.lot_size, nil, property.lot_size_uom, nil, pref)
      render_propdata 'Lot Size', html, format
    elsif good_value?(property.size_min) || good_value?(property.size_max)
      pref = preferred_readable_unit(:property)
      html = display_units(property.size_min, property.size_max, property.size_min_uom, property.size_max_uom, pref)
      render_propdata 'Space Available', html, format
    end
  end

...

  def preferred_unit type    # line 202
    search_params.send("#{type}_unit") || client_state.send("#{type}_unit")
  end

...
end

app-views-search-print-_property.html.haml

- primary_contact = property.eager_primary_contact
.property.breakable{href: property_path_with_params(property)}
  .row
    .col-xs-4
      .row
        .col-xs-5
          .icon-pictures
            - if property.main_photo && property.main_photo.file_exists?('icon')
              .picture
                %img{src: property.main_photo.url('icon')}
            - else
              .picture-generic
            .picture-caption
              = property.type
        .col-xs-7
          .row
            .col-xs-12.data-section
              .property-name= property.name
              .location
                != property.address1
                - unless property.address2.blank?
                  != property.address2
                - unless property.address3.blank?
                  != property.address3
              .location= property.location
    .col-xs-8
      .row
        .col-xs-6
          .row
            .col-xs-7.data-section
              .prop-info
                = format_property_size property, 'two_lines'
        - unless property.contact_properties.empty?
          .contact
            .col-xs-6
              - if primary_contact
                %span.nowrap= primary_contact.name
                %span.nowrap= primary_contact.company_name.present? ? ' - ' + primary_contact.company_name : ''
                %span.prop-value= primary_contact.telephone
      .row
        .col-xs-12
          .description= property.description

spec-views-search-print-_property.html.haml_spec.rb

describe 'search/print/_property.html.haml', type: :view do
  it 'displays the page' do
    property = build(:property)
    render 'search/print/property', property: property
    assert_select ":match('href', ?)", "/property/#{property.property_id}"
  end
end

ze-error.txt

(note that the above files are severely truncated so the line #s won't match)

  
  1) search/print/_property.html.haml displays the page
     Failure/Error: search_params.send("#{type}_unit") || client_state.send("#{type}_unit")
     
     ActionView::Template::Error:
       undefined local variable or method `search_params' for #<#<Class:0x007fb297cca2d0>:0x007fb297c7a280>
     # ./app/helpers/search_helper.rb:203:in `preferred_unit'
     # ./app/helpers/search_helper.rb:153:in `preferred_readable_unit'
     # ./app/helpers/search_helper.rb:172:in `format_property_size'
     # ./app/views/search/print/_property.html.haml:32:in `_app_views_search_print__property_html_haml___457751931363389149_70202514494660'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/template.rb:145:in `block in render'
     # /Users/bronson/.gem/ruby/2.2.2/gems/activesupport-4.2.5/lib/active_support/notifications.rb:164:in `block in instrument'
     # /Users/bronson/.gem/ruby/2.2.2/gems/activesupport-4.2.5/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
     # /Users/bronson/.gem/ruby/2.2.2/gems/activesupport-4.2.5/lib/active_support/notifications.rb:164:in `instrument'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/template.rb:333:in `instrument'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/template.rb:143:in `render'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/renderer/partial_renderer.rb:339:in `render_partial'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/renderer/partial_renderer.rb:310:in `block in render'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/renderer/abstract_renderer.rb:39:in `block in instrument'
     # /Users/bronson/.gem/ruby/2.2.2/gems/activesupport-4.2.5/lib/active_support/notifications.rb:164:in `block in instrument'
     # /Users/bronson/.gem/ruby/2.2.2/gems/activesupport-4.2.5/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
     # /Users/bronson/.gem/ruby/2.2.2/gems/activesupport-4.2.5/lib/active_support/notifications.rb:164:in `instrument'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/renderer/abstract_renderer.rb:39:in `instrument'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/renderer/partial_renderer.rb:309:in `render'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/renderer/renderer.rb:47:in `render_partial'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/helpers/rendering_helper.rb:35:in `render'
     # /Users/bronson/.gem/ruby/2.2.2/gems/haml-4.0.7/lib/haml/helpers/action_view_mods.rb:12:in `render_with_haml'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/test_case.rb:199:in `render'
     # /Users/bronson/.gem/ruby/2.2.2/gems/actionview-4.2.5/lib/action_view/test_case.rb:120:in `render'
     # ./spec/views/search/print/_property.html.haml_spec.rb:4:in `block (2 levels) in <top (required)>'
     # /Users/bronson/.gem/ruby/2.2.2/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:268:in `load'
     # /Users/bronson/.gem/ruby/2.2.2/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:268:in `block in load'
     # /Users/bronson/.gem/ruby/2.2.2/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:240:in `load_dependency'
     # /Users/bronson/.gem/ruby/2.2.2/gems/activesupport-4.2.5/lib/active_support/dependencies.rb:268:in `load'
     # /Users/bronson/.gem/ruby/2.2.2/gems/spring-commands-rspec-1.0.4/lib/spring/commands/rspec.rb:18:in `call'
     # -e:1:in `<main>'
     # ------------------
     # --- Caused by: ---
     # NameError:
     #   undefined local variable or method `search_params' for #<#<Class:0x007fb297cca2d0>:0x007fb297c7a280>
     #   ./app/helpers/search_helper.rb:203:in `preferred_unit'