Fix Ruby 2.6+ Logger compatibility issue

[takaokouji]

Summary

Fixes CI failures with Ruby 2.6 and Rails 6.0/6.1 by adding explicit require 'logger'.

Problem

Tests are failing on Ruby 2.6 with the following error:

uninitialized constant ActiveSupport::LoggerThreadSafeLevel::Logger (NameError)

This affects multiple CI jobs:

• Ruby 2.6 Rails 6.0.6 (both SQLite and PostgreSQL)
• Ruby 2.6 Rails 6.1.7 (both SQLite and PostgreSQL)

Root Cause

Ruby 3.1+ moved Logger to a separate gem (logger), requiring explicit loading. While this primarily affects Ruby 3.1+, the issue also manifests with Ruby 2.6 and certain Rails versions where ActiveSupport tries to use Logger::Severity before the Logger class is loaded.

Solution

Add require 'logger' at the top of test/test_helper.rb to ensure Logger is loaded before ActiveSupport attempts to use it.

Testing

This fix should resolve the failing CI jobs while maintaining compatibility with all Ruby/Rails combinations in the test matrix.

🤖 Generated with Claude Code