Outsource the picking of workflow failures to show

This way we can actually write test cases for the picking

Fixes #8851

src/api/app/helpers/webui/webui_helper.rb

@@ -341,5 +341,19 @@ def gravatar_icon(email, size)
   def home_title
     @configuration ? @configuration['title'] : 'Open Build Service'
   end
+
+  def pick_max_problems(remaining_checks, remaining_build_problems, max_shown)
+    show_checks = [max_shown, remaining_checks.length].min
+    show_builds = [max_shown - show_checks, remaining_build_problems.length].min
+    # always prefer one build fail
+    if show_builds == 0 && remaining_build_problems.present?
+      show_builds += 1
+      show_checks -= 1
+    end
+
+    checks = remaining_checks.shift(show_checks)
+    build_problems = remaining_build_problems.shift(show_builds)
+    return checks, build_problems, remaining_checks, remaining_build_problems
+  end
 end
 # rubocop:enable Metrics/ModuleLength

src/api/app/views/webui/staging/workflows/_problems.html.haml

@@ -2,30 +2,27 @@
   max_shown = 5
   project_class = staging_project.name.tr(':.', '_')
   item_project_class = 'hidden-item-' + project_class
-  checks_problems = staging_project.checks.failed
   build_problems = merge_broken_packages(staging_project.broken_packages)
-  total_problems = checks_problems.length + build_problems.length
+  checks, build_problems, remaining_checks, remaining_build_problems =
+    pick_max_problems(staging_project.checks.failed.to_a, build_problems, max_shown)
 
-- if total_problems == 0
+- if checks.empty? && build_problems.empty?
   .text-center
     %i.fas.fa-check-circle.text-success
 - else
-  :ruby
-    rendered_checks_problems = [max_shown - 1, checks_problems.length].min
-    rendered_build_problems = max_shown - rendered_checks_problems
   %ul.list-group.list-group-flush
-    - checks_problems[0..(rendered_checks_problems - 1)].each do |check|
+    - checks.each do |check|
       = render partial: 'status_problems', locals: { check: check }
-    - build_problems[0..(rendered_build_problems - 1)].each do |name, states|
+    - build_problems.each do |name, states|
       = render partial: 'build_problems', locals: { name: name, states: states, staging_project: staging_project }
-    - if total_problems > max_shown
-      - number = total_problems - max_shown
+    - remain_count = remaining_checks.length + remaining_build_problems.length
+    - if remain_count > 0
       %span.collapse{ 'id': item_project_class }
-        - checks_problems[rendered_checks_problems..-1].each do |check|
+        - remaining_checks.each do |check|
           = render partial: 'status_problems', locals: { check: check }
-        - build_problems[rendered_build_problems..-1].each do |name, states|
+        - remaining_build_problems.each do |name, states|
           = render partial: 'build_problems', locals: { name: name, states: states, staging_project: staging_project }
       %li.list-group-item.table-list-group-item
         %a{ 'data-toggle': 'collapse', href: "##{item_project_class}", 'aria-expanded': 'false' }
-          %span.expander See #{number} more
-          %span.collapser See #{number} less
+          %span.expander See #{remain_count} more
+          %span.collapser See #{remain_count} less

src/api/spec/helpers/webui/webui_helper_spec.rb

@@ -248,4 +248,37 @@
       it { expect(toggle_sliced_text(big_text)).to match(/(.+)#{sliced_text}(.+)\[\+\](.+)#{big_text}(.+)\[\-\](.+)/) }
     end
   end
+
+  describe '#pick_max_problems' do
+    let(:max_shown) { 5 }
+    subject { pick_max_problems(checks, builds, max_shown) }
+
+    context 'with no failed checks' do
+      let(:checks) { [] }
+
+      context 'with no fails' do
+        let(:builds) { [] }
+        it { is_expected.to eq([[], [], [], []]) }
+      end
+
+      context 'with 7 fails' do
+        let(:builds) { [1, 2, 3, 4, 5, 6, 7] }
+        it { is_expected.to eq([[], [1, 2, 3, 4, 5], [], [6, 7]]) }
+      end
+    end
+
+    context 'with 7 checks' do
+      let(:checks) { [1, 2, 3, 4, 5, 6, 7] }
+
+      context 'with no fails' do
+        let(:builds) { [] }
+        it { is_expected.to eq([[1, 2, 3, 4, 5], [], [6, 7], []]) }
+      end
+
+      context 'with 7 fails' do
+        let(:builds) { [1, 2, 3, 4, 5, 6, 7] }
+        it { is_expected.to eq([[1, 2, 3, 4], [1], [5, 6, 7], [2, 3, 4, 5, 6, 7]]) }
+      end
+    end
+  end
 end