Pagination, Page 3

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Continuing pagination work, I need to get previous and next links working. I also never actually put links in the a tags, so I will get that working as well.

To get the href working, I add an href expectation to the first pagination expectation from last night:

  it "should have a link to other pages" do
    pagination('foo', 0, 20, 41).
      should have_selector("a",
                           :content => "2",
                           :href    => "/recipes/search?q=foo&page=2")
  end

To drive development of the next / previous link, I write the following examples:

  it "should have a link to the next page if before the last page" do
    pagination('foo', 20, 20, 41).
      should have_selector("a", :content => "Next »")
  end
  it "should not have a link to the next page if on the last page" do
    pagination('foo', 40, 20, 41).
      should have_selector("span", :content => "Next »")
  end
  it "should have a link to the previous page if past the first page" do
    pagination('foo', 20, 20, 41).
      should have_selector("a", :content => "« Previous")
  end
  it "should not have a link to the next page if on the first page" do
    pagination('foo', 0, 20, 41).
      should have_selector("span", :content => "« Previous")
  end

Working through each of these examples, I end up with the following, longish implementation:

    def pagination(query, skip, limit, total)
      last_page    = (total + limit - 1) / limit
      current_page = skip / limit + 1

      link = "/recipes/search?q=#{query}"

      links = []

      links <<
        if current_page == 1
          %Q|<span class="inactive">« Previous</span>|
        else
          %Q|<a href="#{link}&page=#{current_page - 1}">« Previous</a>|
        end

      links << (1..last_page).map do |page|
        %Q|<a href="#{link}&page=#{page}">#{page}</a>|
      end

      links <<
        if current_page == last_page
          %Q|<span class="inactive">Next »</span>|
        else
          %Q|<a href="#{link}&page=#{current_page + 1}">Next »</a>|
        end

      %Q|<div class="pagination">#{links.join}</div>|
    end

I can DRY that up some, especially the conditionals around the previous / next links. For now, I will get it done and worry about doing it right another day. At least the repetition is small and all contained within a single method.

The addition of the query parameter to the pagination helper requires a bunch of clean-up in both specs and code. Once that is done, it is back on out to the cucumber feature:

    Scenario: Paginating results

      Given 50 yummy recipes
      And a 0.5 second wait to allow the search index to be updated
      When I search for "yummy"
      Then I should see 20 results
      And I should see 3 pages of results
      And I should not be able to go to a previous page
      When I click page 3
      Then I should see 10 results
      And I should not be able to go to a next page
      When I click the previous page
      Then I should see 20 results
      And I should be able to go to a previous page
      When I click the next page
      Then I should see 10 results
      When I visit page -1
      Then I should see page 1
      When I visit page "foo"
      Then I should see page 1
      When I visit page 4
      Then I should see page 1

To verify that I should not be able to go to a previous page, I use the following:

Then /^I should not be able to go to a previous page$/ do
  response.should have_selector(".pagination span", :content => "« Previous")
end

Running the spec, I find my final failure for today:

cstrom@jaynestown:~/repos/eee-code$ cucumber features/recipe_search.feature -n -s "Paginating results"
Feature: Search for recipes

  So that I can find one recipe among many
  As a web user
  I want to be able search recipes

  Scenario: Paginating results
    Given 50 yummy recipes
    And a 0.5 second wait to allow the search index to be updated
    When I search for "yummy"
    Then I should see 20 results
    And I should see 3 pages of results
    And I should not be able to go to a previous page
    When I click page 3
    Then I should see 10 results
      expected following output to contain a <table a/> tag:
      <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
      <html><body>
      <table>
      <tr>
      <th>Name</th>
          <th>Date</th>
        </tr>
      <tr class="row0">
      <td>
            <a href="/recipes/id-0-yummy">yummy recipe 0</a>
          </td>
          <td>2009-04-22</td>
        </tr>
      <tr class="row1">
      <td>
            <a href="/recipes/id-1-yummy">yummy recipe 1</a>
          </td>
          <td>2009-04-22</td>
        </tr>
      <tr class="row0">
...

Still on recipe 0? Oops, I have yet to connect the page parameters to the RestClient calls to couchdb-lucene.

I do not mind stopping with a failing test. Quite the opposite, I know exactly where to start tomorrow.