Add e2e testcase link format cop

rubocop/cop/qa/testcase_link_format.rb

+# frozen_string_literal: true
+
+require_relative '../../qa_helpers'
+
+module RuboCop
+  module Cop
+    module QA
+      # This cop checks for correct format of testcase links across e2e specs
+      #
+      # @example
+      #
+      #   # bad
+      #   it 'some test', testcase: 'https://gitlab.com/gitlab-org/quality/testcases/-/issues/557'
+      #   it 'another test, testcase: 'https://gitlab.com/gitlab-org/quality/testcases/-/quality/test_cases/2455'
+      #
+      #   # good
+      #   it 'some test', testcase: 'https://gitlab.com/gitlab-org/gitlab/-/quality/test_cases/348312'
+      #   it 'another test, testcase: 'https://gitlab.com/gitlab-org/gitlab/-/quality/test_cases/348236'
+      class TestcaseLinkFormat < RuboCop::Cop::Cop
+        include QAHelpers
+
+        TESTCASE_FORMAT = %r{https://gitlab.com/gitlab-org/gitlab/-/quality/test_cases/\d+}.freeze
+        MESSAGE = "Testcase link format incorrect. Please link a test case from the GitLab project. See: https://docs.gitlab.com/ee/development/testing_guide/end_to_end/best_practices.html#link-a-test-to-its-test-case."
+
+        def_node_matcher :testcase_link_format, <<~PATTERN
+          (block
+            (send nil? ...
+              ...
+              (hash
+                (pair
+                  (sym :testcase)
+                  (str $_))...)...)...)
+        PATTERN
+
+        def on_block(node)
+          return unless in_qa_file?(node)
+
+          testcase_link_format(node) do |link|
+            add_offense(node, message: MESSAGE % link) unless TESTCASE_FORMAT =~ link
+          end
+        end
+      end
+    end
+  end
+end

spec/rubocop/cop/qa/testcase_link_format_spec.rb

+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+
+require_relative '../../../../rubocop/cop/qa/testcase_link_format'
+
+RSpec.describe RuboCop::Cop::QA::TestcaseLinkFormat do
+  let(:source_file) { 'qa/page.rb' }
+  let(:msg) { 'Testcase link format incorrect. Please link a test case from the GitLab project. See: https://docs.gitlab.com/ee/development/testing_guide/end_to_end/best_practices.html#link-a-test-to-its-test-case.' }
+
+  subject(:cop) { described_class.new }
+
+  context 'in a QA file' do
+    before do
+      allow(cop).to receive(:in_qa_file?).and_return(true)
+    end
+
+    it "registers an offense for a testcase link for an issue" do
+      node = "it 'another test', testcase: 'https://gitlab.com/gitlab-org/gitlab/-/issues/557' do"
+
+      expect_offense(<<-RUBY, node: node, msg: msg)
+        %{node}
+        ^{node} %{msg}
+        end
+      RUBY
+    end
+
+    it "registers an offense for a testcase link for the wrong project" do
+      node = "it 'another test', testcase: 'https://gitlab.com/gitlab-org/quality/testcases/-/quality/test_cases/2455' do"
+
+      expect_offense(<<-RUBY, node: node, msg: msg)
+        %{node}
+        ^{node} %{msg}
+        end
+      RUBY
+    end
+
+    it "doesnt offend if testcase link is correct" do
+      expect_no_offenses(<<-RUBY)
+        it 'some test', testcase: 'https://gitlab.com/gitlab-org/gitlab/-/quality/test_cases/348312' do
+        end
+      RUBY
+    end
+  end
+end