1 files changed, 67 insertions, 0 deletions
diff --git a/rubocop/cop/gitlab/no_code_coverage_comment.rb b/rubocop/cop/gitlab/no_code_coverage_comment.rb
new file mode 100644
index 00000000000..3b989930026
--- /dev/null
+++ b/rubocop/cop/gitlab/no_code_coverage_comment.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Gitlab
+      # Discourages the use of `# :nocov:` to exclude code from coverage report.
+      #
+      # The nocov token can be configured via `CommentToken` option and defaults
+      # to `'nocov'`.
+      #
+      # @example CommentToken: 'nocov' (default)
+      #
+      #   # bad
+      #   # :nocov:
+      #   def method
+      #   end
+      #   # :nocov:
+      #
+      #   # good
+      #   def method
+      #   end
+      #
+      class NoCodeCoverageComment < RuboCop::Cop::Base
+        include RangeHelp
+
+        MSG = 'The use of %<nocov_comment>s is discouraged. All code must have tests. See https://docs.gitlab.com/ee/development/contributing/merge_request_workflow.html#testing'
+
+        DEFAULT_COMMENT_TOKEN = 'nocov'
+
+        def on_new_investigation
+          super
+
+          nocov_token = cop_config.fetch('CommentToken', DEFAULT_COMMENT_TOKEN)
+          nocov_comment = ":#{nocov_token}:"
+          # See https://github.com/simplecov-ruby/simplecov/blob/v0.21.2/lib/simplecov/lines_classifier.rb#L16
+          regexp = /^(?:\s*)#(?:\s*)(?::#{nocov_token}:)/
+
+          processed_source.comments.each do |comment|
+            register_offense(comment, nocov_comment) if regexp.match?(comment.text)
+          end
+        end
+
+        private
+
+        def register_offense(comment, nocov_comment)
+          range = range_of_offense(comment, nocov_comment)
+          message = format(MSG, nocov_comment: nocov_comment)
+
+          add_offense(range, message: message)
+        end
+
+        def range_of_offense(comment, name)
+          start_pos = comment_start(comment) + token_indentation(comment, name)
+          range_between(start_pos, start_pos + name.size)
+        end
+
+        def comment_start(comment)
+          comment.loc.expression.begin_pos
+        end
+
+        def token_indentation(comment, name)
+          comment.text.index(name)
+        end
+      end
+    end
+  end
+end