1 files changed, 99 insertions, 0 deletions
diff --git a/spec/tooling/danger/specs/feature_category_suggestion_spec.rb b/spec/tooling/danger/specs/feature_category_suggestion_spec.rb
new file mode 100644
index 00000000000..3956553f488
--- /dev/null
+++ b/spec/tooling/danger/specs/feature_category_suggestion_spec.rb
@@ -0,0 +1,99 @@
+# frozen_string_literal: true
+
+require 'gitlab/dangerfiles/spec_helper'
+
+require_relative '../../../../tooling/danger/specs'
+require_relative '../../../../tooling/danger/project_helper'
+
+RSpec.describe Tooling::Danger::Specs::FeatureCategorySuggestion, feature_category: :tooling do
+  include_context "with dangerfile"
+
+  let(:fake_danger) { DangerSpecHelper.fake_danger.include(Tooling::Danger::Specs) }
+  let(:fake_project_helper) { instance_double('Tooling::Danger::ProjectHelper') }
+  let(:filename) { 'spec/foo_spec.rb' }
+
+  let(:template) do
+    <<~SUGGESTION_MARKDOWN.chomp
+    ```suggestion
+    %<suggested_line>s
+    ```
+
+    Consider adding `feature_category: <feature_category_name>` for this example if it is not set already.
+    See [testing best practices](https://docs.gitlab.com/ee/development/testing_guide/best_practices.html#feature-category-metadata).
+    SUGGESTION_MARKDOWN
+  end
+
+  let(:file_lines) do
+    [
+      " require 'spec_helper'",
+      " \n",
+      " RSpec.describe Projects::SummaryController, feature_category: :planning_analytics do",
+      " end",
+      "RSpec.describe Projects::SummaryController do",
+      "  let_it_be(:user) { create(:user) }",
+      " end",
+      " describe 'GET \"time_summary\"' do",
+      " end",
+      " RSpec.describe Projects::SummaryController do",
+      "  let_it_be(:user) { create(:user) }",
+      " end",
+      " describe 'GET \"time_summary\"' do",
+      " end",
+      " \n",
+      "RSpec.describe Projects :aggregate_failures,",
+      "  feature_category: planning_analytics do",
+      " \n",
+      "RSpec.describe Epics :aggregate_failures,",
+      "  ee: true do",
+      "\n",
+      "RSpec.describe Issues :aggregate_failures,",
+      "  feature_category: :team_planning do",
+      "\n",
+      "RSpec.describe MergeRequest :aggregate_failures,",
+      "  :js,",
+      "  feature_category: :team_planning do"
+    ]
+  end
+
+  let(:changed_lines) do
+    [
+      "+ RSpec.describe Projects::SummaryController, feature_category: :planning_analytics do",
+      "+RSpec.describe Projects::SummaryController do",
+      "+ let_it_be(:user) { create(:user) }",
+      "- end",
+      "+ describe 'GET \"time_summary\"' do",
+      "+ RSpec.describe Projects::SummaryController do",
+      "+RSpec.describe Projects :aggregate_failures,",
+      "+  feature_category: planning_analytics do",
+      "+RSpec.describe Epics :aggregate_failures,",
+      "+  ee: true do",
+      "+RSpec.describe Issues :aggregate_failures,",
+      "+RSpec.describe MergeRequest :aggregate_failures,",
+      "+  :js,",
+      "+  feature_category: :team_planning do",
+      "+RSpec.describe 'line in commit diff but no longer in working copy' do"
+    ]
+  end
+
+  subject(:specs) { fake_danger.new(helper: fake_helper) }
+
+  before do
+    allow(specs).to receive(:project_helper).and_return(fake_project_helper)
+    allow(specs.helper).to receive(:changed_lines).with(filename).and_return(changed_lines)
+    allow(specs.project_helper).to receive(:file_lines).and_return(file_lines)
+  end
+
+  it 'adds suggestions at the correct lines', :aggregate_failures do
+    [
+      { suggested_line: "RSpec.describe Projects::SummaryController do", number: 5 },
+      { suggested_line: " RSpec.describe Projects::SummaryController do", number: 10 },
+      { suggested_line: "RSpec.describe Epics :aggregate_failures,", number: 19 }
+
+    ].each do |test_case|
+      comment = format(template, suggested_line: test_case[:suggested_line])
+      expect(specs).to receive(:markdown).with(comment, file: filename, line: test_case[:number])
+    end
+
+    specs.add_suggestions_for(filename)
+  end
+end