Merge branch 'task/404981' into 'master'

Fix edges in KeysetPaginationHelpers spec helper and add specs

See merge request !120572



Merged-by: charlie ablett <cablett@gitlab.com>
Approved-by: charlie ablett <cablett@gitlab.com>
Reviewed-by: Peter Leitzen <pleitzen@gitlab.com>
Co-authored-by: Michael Becker <11881043-wandering_person@users.noreply.gitlab.com>

spec/support/helpers/keyset_pagination_helpers.rb

@@ -7,14 +7,17 @@ def pagination_links(response)
 
     link.split(',').filter_map do |link|
       match = link.match(/<(?<url>.*)>; rel="(?<rel>\w+)"/)
-      break nil unless match
+      next unless match
 
       { url: match[:url], rel: match[:rel] }
     end
   end
 
   def pagination_params_from_next_url(response)
-    next_url = pagination_links(response).find { |link| link[:rel] == 'next' }[:url]
+    next_link = pagination_links(response).find { |link| link[:rel] == 'next' }
+    next_url = next_link&.fetch(:url)
+    return unless next_url
+
     Rack::Utils.parse_query(URI.parse(next_url).query)
   end
 end

spec/support_specs/helpers/keyset_pagination_helpers_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe KeysetPaginationHelpers, feature_category: :api do
+  include described_class
+
+  let(:headers) { { 'LINK' => %(<#{url}>; rel="#{rel}") } }
+  let(:response) { instance_double('HTTParty::Response', headers: headers) }
+  let(:rel) { 'next' }
+  let(:url) do
+    'http://127.0.0.1:3000/api/v4/projects/7/audit_eve' \
+      'nts?cursor=eyJpZCI6IjYyMjAiLCJfa2QiOiJuIn0%3D&id=7&o' \
+      'rder_by=id&page=1&pagination=keyset&per_page=2'
+  end
+
+  describe '#pagination_links' do
+    subject { pagination_links(response) }
+
+    let(:expected_result) { [{ url: url, rel: rel }] }
+
+    it { is_expected.to eq expected_result }
+
+    context 'with a partially malformed LINK header' do
+      # malformed as the regxe is expecting the url to be surrounded by `<>`
+      let(:headers) do
+        { 'LINK' => %(<#{url}>; rel="next", GARBAGE, #{url}; rel="prev") }
+      end
+
+      it { is_expected.to eq expected_result }
+    end
+
+    context 'with a malformed LINK header' do
+      # malformed as the regxe is expecting the url to be surrounded by `<>`
+      let(:headers) { { 'LINK' => %(rel="next", GARBAGE, #{url}; rel="prev") } }
+      let(:expected_result) { [] }
+
+      it { is_expected.to eq expected_result }
+    end
+  end
+
+  describe '#pagination_params_from_next_url' do
+    subject { pagination_params_from_next_url(response) }
+
+    let(:expected_result) do
+      {
+        'cursor' => 'eyJpZCI6IjYyMjAiLCJfa2QiOiJuIn0=',
+        'id' => '7',
+        'order_by' => 'id',
+        'page' => '1',
+        'pagination' => 'keyset',
+        'per_page' => '2'
+      }
+    end
+
+    it { is_expected.to eq expected_result }
+
+    context 'with both prev and next rel links' do
+      let(:prev_url) do
+        'http://127.0.0.1:3000/api/v4/projects/7/audit_eve' \
+          'nts?cursor=foocursor&id=8&o' \
+          'rder_by=id&page=0&pagination=keyset&per_page=2'
+      end
+
+      let(:headers) do
+        { 'LINK' => %(<#{url}>; rel="next", <#{prev_url}>; rel="prev") }
+      end
+
+      it { is_expected.to eq expected_result }
+    end
+
+    context 'with a partially malformed LINK header' do
+      # malformed as the regxe is expecting the url to be surrounded by `<>`
+      let(:headers) do
+        { 'LINK' => %(<#{url}>; rel="next", GARBAGE, #{url}; rel="prev") }
+      end
+
+      it { is_expected.to eq expected_result }
+    end
+
+    context 'with a malformed LINK header' do
+      # malformed as the regxe is expecting the url to be surrounded by `<>`
+      let(:headers) { { 'LINK' => %(rel="next", GARBAGE, #{url}; rel="prev") } }
+
+      it { is_expected.to be nil }
+    end
+  end
+end