Always require spec_helper first in CI

This can prevent from requiring fast_spec_helper before
requiring spec_helper, and in that case it'll break.
(Rails cannot be properly loaded this way)

scripts/rspec_helpers.sh

@@ -90,7 +90,7 @@ function rspec_simple_job() {
 
   export NO_KNAPSACK="1"
 
-  bin/rspec --color --format documentation --format RspecJunitFormatter --out junit_rspec.xml ${rspec_opts}
+  bin/rspec -Ispec -rspec_helper --color --format documentation --format RspecJunitFormatter --out junit_rspec.xml ${rspec_opts}
 }
 
 function rspec_paralellized_job() {
@@ -143,7 +143,7 @@ function rspec_paralellized_job() {
 
   export MEMORY_TEST_PATH="tmp/memory_test/${report_name}_memory.csv"
 
-  knapsack rspec "-Ispec --color --format documentation --format RspecJunitFormatter --out junit_rspec.xml ${rspec_opts}"
+  knapsack rspec "-Ispec -rspec_helper --color --format documentation --format RspecJunitFormatter --out junit_rspec.xml ${rspec_opts}"
 
   date
 }

spec/fast_spec_helper.rb

 # frozen_string_literal: true
 
-# When running in CI environment, we need to load a full `spec_helper`
-if ENV['CI']
-  require_relative 'spec_helper'
+#  $" is $LOADED_FEATURES, but RuboCop didn't like it
+if $".include?(File.expand_path('spec_helper.rb', __dir__))
+  # There's no need to load anything here if spec_helper is already loaded
+  # because spec_helper is more extensive than fast_spec_helper
   return
 end
 

spec/spec_helper.rb

 # frozen_string_literal: true
 
+#  $" is $LOADED_FEATURES, but RuboCop didn't like it
+if $".include?(File.expand_path('fast_spec_helper.rb', __dir__))
+  warn 'Detected fast_spec_helper is loaded first than spec_helper.'
+  warn 'If running test files using both spec_helper and fast_spec_helper,'
+  warn 'make sure test file with spec_helper is loaded first.'
+  abort 'Aborting...'
+end
+
 require './spec/simplecov_env'
 SimpleCovEnv.start!