Move `simplecov` config into `rails_helper` (#30302)

.simplecov

@@ -1,22 +0,0 @@
-# frozen_string_literal: true
-
-if ENV['CI']
-  require 'simplecov-lcov'
-  SimpleCov::Formatter::LcovFormatter.config.report_with_single_file = true
-  SimpleCov.formatter = SimpleCov::Formatter::LcovFormatter
-else
-  SimpleCov.formatter = SimpleCov::Formatter::HTMLFormatter
-end
-
-SimpleCov.start 'rails' do
-  enable_coverage :branch
-
-  add_filter 'lib/linter'
-
-  add_group 'Libraries', 'lib'
-  add_group 'Policies', 'app/policies'
-  add_group 'Presenters', 'app/presenters'
-  add_group 'Serializers', 'app/serializers'
-  add_group 'Services', 'app/services'
-  add_group 'Validators', 'app/validators'
-end

config/initializers/simple_cov_source_file.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+# TODO: https://github.com/simplecov-ruby/simplecov/pull/1084
+# Patches this missing condition, monitor for upstream fix
+
+module SimpleCov
+  module SourceFileExtensions
+    def build_branches
+      coverage_branch_data = coverage_data.fetch('branches', {}) || {} # Add the final empty hash in case where 'branches' is present, but returns nil
+      branches = coverage_branch_data.flat_map do |condition, coverage_branches|
+        build_branches_from(condition, coverage_branches)
+      end
+
+      process_skipped_branches(branches)
+    end
+  end
+end
+
+SimpleCov::SourceFile.prepend(SimpleCov::SourceFileExtensions) if defined?(SimpleCov::SourceFile)

spec/rails_helper.rb

@@ -2,6 +2,31 @@
 
 ENV['RAILS_ENV'] ||= 'test'
 
+unless ENV['DISABLE_SIMPLECOV'] == 'true'
+  require 'simplecov'
+
+  SimpleCov.start 'rails' do
+    if ENV['CI']
+      require 'simplecov-lcov'
+      formatter SimpleCov::Formatter::LcovFormatter
+      formatter.config.report_with_single_file = true
+    else
+      formatter SimpleCov::Formatter::HTMLFormatter
+    end
+
+    enable_coverage :branch
+
+    add_filter 'lib/linter'
+
+    add_group 'Libraries', 'lib'
+    add_group 'Policies', 'app/policies'
+    add_group 'Presenters', 'app/presenters'
+    add_group 'Serializers', 'app/serializers'
+    add_group 'Services', 'app/services'
+    add_group 'Validators', 'app/validators'
+  end
+end
+
 # This needs to be defined before Rails is initialized
 STREAMING_PORT = ENV.fetch('TEST_STREAMING_PORT', '4020')
 ENV['STREAMING_API_BASE_URL'] = "http://localhost:#{STREAMING_PORT}"

spec/spec_helper.rb

@@ -1,9 +1,5 @@
 # frozen_string_literal: true
 
-unless ENV['DISABLE_SIMPLECOV'] == 'true'
-  require 'simplecov' # Configuration details loaded from .simplecov
-end
-
 RSpec.configure do |config|
   config.example_status_persistence_file_path = 'tmp/rspec/examples.txt'
   config.expect_with :rspec do |expectations|