Add support for testing with multiple Rails versions

.github/workflows/ci.yml

@@ -8,6 +8,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        rails:
+          - '5.2'
+          - '6.0'
         ruby:
           - '2.5.x'
           - '2.6.x'
@@ -20,6 +23,7 @@ jobs:
       PGHOST: 127.0.0.1
       PGUSER: postgres
       RAILS_ENV: test
+      RAILS_VERSION: ${{ matrix.rails }}
       CC_TEST_REPORTER_ID: bca4349e32f97919210ac8a450b04904b90683fcdd57d65a22c0f5065482bc22
     services:
       postgres:
@@ -48,7 +52,7 @@ jobs:
         uses: actions/cache@preview
         with:
           path: vendor/bundle
-          key: ${{ runner.os }}-bundle-${{ matrix.ruby }}-${{ matrix.database }}-${{ hashFiles('**/Gemfile') }}
+          key: ${{ runner.os }}-bundle-${{ matrix.ruby }}-${{ matrix.rails }}-${{ matrix.database }}-${{ hashFiles('**/Gemfile') }}
           restore-keys: |
             ${{ runner.os }}-bundle-
       - name: Install bundle

Gemfile

@@ -2,12 +2,15 @@ source 'https://rubygems.org'
 
 gemspec
 
-gem 'rails', '~> 6.0.0'
+rails_version = ENV.fetch('RAILS_VERSION', 6.0).to_f
+gem 'rails', "~> #{rails_version}.0"
 
 # Profiling
 gem 'rack-mini-profiler', group: :development, require: false
 
-gem 'sqlite3', '~> 1.4.1' if ENV['DB'].nil? || ENV['DB'] == 'sqlite'
+if ENV['DB'].nil? || ENV['DB'] == 'sqlite'
+  gem 'sqlite3', rails_version > 5.0 ? '~> 1.4.1' : '~> 1.3.6'
+end
 gem 'mysql2', '~> 0.5.1' if ENV['DB'] == 'mysql'
 gem 'pg',     '~> 1.0'   if ENV['DB'] == 'postgresql'
 gem 'sassc-rails'

spec/dummy/config/application.rb

@@ -22,7 +22,9 @@
 module Dummy
   class Application < Rails::Application
     # Initialize configuration defaults for originally generated Rails version.
-    config.load_defaults 6.0
+    if config.respond_to?(:load_defaults)
+      config.load_defaults ENV['RAILS_VERSION'] || 6.0
+    end
 
     # Settings in config/environments/* take precedence over those specified here.
     # Application configuration can go into files in config/initializers

spec/dummy/config/environments/development.rb

@@ -39,8 +39,10 @@
   # Raise an error on page load if there are pending migrations.
   config.active_record.migration_error = :page_load
 
-  # Highlight code that triggered database queries in logs.
-  config.active_record.verbose_query_logs = true
+  if ActiveRecord::Base.respond_to?(:verbose_query_logs=)
+    # Highlight code that triggered database queries in logs.
+    config.active_record.verbose_query_logs = true
+  end
 
   # Debug mode disables concatenation and preprocessing of assets.
   # This option may cause significant delays in view rendering with a large

spec/dummy/db/migrate/20180409171801_create_series.rb

@@ -1,4 +1,4 @@
-class CreateSeries < ActiveRecord::Migration[5.1]
+class CreateSeries < ActiveRecord::Migration[5.0]
   def change
     create_table :series do |t|
       t.string :name

spec/dummy/db/migrate/20190417070726_create_bookings.rb

@@ -1,4 +1,4 @@
-class CreateBookings < ActiveRecord::Migration[5.2]
+class CreateBookings < ActiveRecord::Migration[5.0]
   def change
     create_table :bookings do |t|
       t.date :from