Add rubocop for expect on Gitlab::Tracking#event

Adds a new RuboCop cop for protecting against doing
expect(Gitlab::Tracking).to receive(:event) within specs.
All existing offending files are added to the .rubocop_todo.yml file and
should be converted at our earliest convenience.

.rubocop_todo.yml

@@ -186,6 +186,35 @@ RSpec/ContextWording:
 RSpec/ExpectChange:
   Enabled: false
 
+# Offense count: 47
+RSpec/ExpectGitlabTracking:
+  Exclude:
+    - 'ee/spec/controllers/groups/analytics/coverage_reports_controller_spec.rb'
+    - 'ee/spec/controllers/projects/settings/operations_controller_spec.rb'
+    - 'ee/spec/controllers/registrations_controller_spec.rb'
+    - 'ee/spec/requests/api/visual_review_discussions_spec.rb'
+    - 'ee/spec/services/epics/issue_promote_service_spec.rb'
+    - 'spec/controllers/groups/registry/repositories_controller_spec.rb'
+    - 'spec/controllers/groups_controller_spec.rb'
+    - 'spec/controllers/projects/registry/repositories_controller_spec.rb'
+    - 'spec/controllers/projects/registry/tags_controller_spec.rb'
+    - 'spec/controllers/projects/settings/operations_controller_spec.rb'
+    - 'spec/controllers/registrations_controller_spec.rb'
+    - 'spec/lib/api/helpers_spec.rb'
+    - 'spec/lib/gitlab/experimentation_spec.rb'
+    - 'spec/mailers/notify_spec.rb'
+    - 'spec/models/project_services/prometheus_service_spec.rb'
+    - 'spec/requests/api/project_container_repositories_spec.rb'
+    - 'spec/services/clusters/applications/check_installation_progress_service_spec.rb'
+    - 'spec/services/issues/zoom_link_service_spec.rb'
+    - 'spec/support/helpers/snowplow_helpers.rb'
+    - 'spec/support/shared_examples/controllers/trackable_shared_examples.rb'
+    - 'spec/support/shared_examples/requests/api/container_repositories_shared_examples.rb'
+    - 'spec/support/shared_examples/requests/api/discussions_shared_examples.rb'
+    - 'spec/support/shared_examples/requests/api/packages_shared_examples.rb'
+    - 'spec/support/shared_examples/requests/api/tracking_shared_examples.rb'
+    - 'spec/support/snowplow.rb'
+
 # Offense count: 751
 RSpec/ExpectInHook:
   Enabled: false

rubocop/cop/rspec/expect_gitlab_tracking.rb

+# frozen_string_literal: true
+
+require 'rack/utils'
+
+module RuboCop
+  module Cop
+    module RSpec
+      # This cop checks for `expect(Gitlab::Tracking).to receive(:event)` usage in specs.
+      # See /spec/support/helpers/snowplow_helpers.rb for details on the replacement.
+      #
+      # @example
+      #
+      # # bad
+      # it 'expects a snowplow event' do
+      #   expect(Gitlab::Tracking).to receive(:event).with("Category", "action", ...)
+      # end
+      #
+      # # good
+      # it 'expects a snowplow event', :snowplow do
+      #   expect_snowplow_event(category: "Category", action: "action", ...)
+      # end
+      #
+      # # bad
+      # it 'does not expect a snowplow event' do
+      #   expect(Gitlab::Tracking).not_to receive(:event)
+      # end
+      #
+      # # good
+      # it 'does not expect a snowplow event', :snowplow do
+      #   expect_no_snowplow_event
+      # end
+      class ExpectGitlabTracking < RuboCop::Cop::Cop
+        MSG = 'Do not expect directly on `Gitlab::Tracking#event`, add the `snowplow` annotation and use ' \
+              '`expect_snowplow_event` instead. ' \
+              'See https://docs.gitlab.com/ee/development/testing_guide/best_practices.html#test-snowplow-events'
+
+        def_node_matcher :expect_gitlab_tracking?, <<~PATTERN
+          (send
+            (send nil? {:expect :allow}
+              (const (const nil? :Gitlab) :Tracking)
+            )
+            ${:to :to_not :not_to}
+            {
+              (
+                send nil? {:receive :have_received} (sym :event) ...
+              )
+
+              (send
+                (send nil? {:receive :have_received} (sym :event)) ...
+              )
+            }
+            ...
+          )
+        PATTERN
+
+        RESTRICT_ON_SEND = [:expect, :allow].freeze
+
+        def on_send(node)
+          return unless expect_gitlab_tracking?(node)
+
+          add_offense(node)
+        end
+      end
+    end
+  end
+end

spec/rubocop/cop/rspec/expect_gitlab_tracking_spec.rb

+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+
+require_relative '../../../../rubocop/cop/rspec/expect_gitlab_tracking'
+
+RSpec.describe RuboCop::Cop::RSpec::ExpectGitlabTracking do
+  include CopHelper
+
+  let(:source_file) { 'spec/foo_spec.rb' }
+
+  subject(:cop) { described_class.new }
+
+  good_samples = [
+    'expect_snowplow_event(category: nil, action: nil)',
+    'expect_snowplow_event(category: "EventCategory", action: "event_action")',
+    'expect_snowplow_event(category: "EventCategory", action: "event_action", label: "label", property: "property")',
+    'expect_no_snowplow_event'
+  ]
+
+  bad_samples = [
+    'expect(Gitlab::Tracking).to receive(:event)',
+    'expect(Gitlab::Tracking).to_not receive(:event)',
+    'expect(Gitlab::Tracking).not_to receive(:event)',
+    'expect(Gitlab::Tracking).to_not receive(:event).with("EventCategory", "event_action")',
+    'expect(Gitlab::Tracking).not_to receive(:event).with("EventCategory", "event_action")',
+    'expect(Gitlab::Tracking).to receive(:event).with("EventCategory", "event_action", label: "label", property: "property")',
+    'expect(Gitlab::Tracking).to have_received(:event).with("EventCategory", "event_action")',
+    'expect(Gitlab::Tracking).to_not have_received(:event).with("EventCategory", "event_action")',
+    'expect(Gitlab::Tracking).not_to have_received(:event).with("EventCategory", "event_action")',
+    'allow(Gitlab::Tracking).to receive(:event).and_call_original'
+  ]
+
+  good_samples.each do |good|
+    context "good: #{good}" do
+      it 'does not register an offense' do
+        inspect_source(good)
+
+        expect(cop.offenses).to be_empty
+      end
+    end
+  end
+
+  bad_samples.each do |bad|
+    context "bad: #{bad}" do
+      it 'registers an offense', :aggregate_failures do
+        inspect_source(bad, source_file)
+
+        expect(cop.offenses.size).to eq(1)
+        expect(cop.offenses.map(&:line)).to eq([1])
+        expect(cop.highlights).to eq([bad])
+
+        msg = cop.offenses.first.message
+
+        expect(msg).to match(
+          /Do not expect directly on `Gitlab::Tracking#event`/
+        )
+        expect(msg).to match(/add the `snowplow` annotation/)
+        expect(msg).to match(/use `expect_snowplow_event` instead/)
+      end
+    end
+  end
+end