Add new non_existing_record_id/non_existing_record_iid spec helpers

Signed-off-by: Rémy Coutable <remy@rymai.me>

doc/development/testing_guide/best_practices.md

@@ -78,6 +78,10 @@ FDOC=1 bin/rspec spec/[path]/[to]/[spec].rb
 - Use `focus: true` to isolate parts of the specs you want to run.
 - Use [`:aggregate_failures`](https://relishapp.com/rspec/rspec-core/docs/expectation-framework-integration/aggregating-failures) when there is more than one expectation in a test.
 - For [empty test description blocks](https://github.com/rubocop-hq/rspec-style-guide#it-and-specify), use `specify` rather than `it do` if the test is self-explanatory.
+- Use `non_existing_record_id`/`non_existing_record_iid`/`non_existing_record_access_level`
+  when you need an ID/IID/access level that doesn't actually exists. Using 123, 1234,
+  or even 999 is brittle as these IDs could actually exist in the database in the
+  context of a CI run.
 
 ### Coverage
 

spec/spec_helper.rb

@@ -100,6 +100,7 @@ RSpec.configure do |config|
   config.include ExpectOffense
   config.include FactoryBot::Syntax::Methods
   config.include FixtureHelpers
+  config.include NonExistingRecordsHelpers
   config.include GitlabRoutingHelper
   config.include StubFeatureFlags
   config.include StubExperiments

spec/support/non_existing_records_helper.rb

+# frozen_string_literal: true
+
+module NonExistingRecordsHelpers
+  # Max value for PG `serial` type: https://www.postgresql.org/docs/12/datatype-numeric.html
+  ACTIVE_MODEL_INTEGER_MAX = 2147483647
+
+  def non_existing_record_id
+    ACTIVE_MODEL_INTEGER_MAX
+  end
+  alias_method :non_existing_record_iid, :non_existing_record_id
+  alias_method :non_existing_record_access_level, :non_existing_record_id
+end