travis test under rails 6 edge using 'appraisal' gem

.gitignore

@@ -9,3 +9,4 @@
 /spec/internal/tmp/cache
 /tmp/
 .byebug_history
+/gemfiles/*.lock

.travis.yml

@@ -8,10 +8,14 @@ language: ruby
 cache: bundler
 rvm:
   - 2.4
-  - 2.5.0
-env:
-  - RAILS_GEM="~> 5.0.0" PG_GEM="~> 0.18"
-  - RAILS_GEM="~> 5.1.0"
-  - RAILS_GEM=">= 5.2.0.rc2,< 5.3.0"
+  - 2.5.1
+gemfile:
+  - gemfiles/rails_5_0.gemfile
+  - gemfiles/rails_5_1.gemfile
+  - gemfiles/rails_5_2.gemfile
+  - gemfiles/rails_edge_6.gemfile
 before_install:
   - gem install bundler -v 1.14.6
+matrix:
+  allow_failures:
+  - gemfile: gemfiles/rails_edge_6.gemfile

Appraisals

@@ -0,0 +1,40 @@
+appraise "rails-5-0" do
+  gem 'combustion', '~> 0.9.0'
+
+  gem "rails", "~> 5.0.0"
+
+  # rails 5.1+ includes it by default, but rails 5.0 needs it:
+  gem 'rails-ujs', require: false
+
+  # Rails 5 won't work with pg 1.0 even though it doesn't say so
+  gem "pg",  "~> 0.18"
+end
+
+appraise "rails-5-1" do
+  gem 'combustion', '~> 0.9.0'
+
+  gem "rails", "~> 5.1.0"
+
+  gem "pg", "~> 1.0"
+end
+
+appraise "rails-5-2" do
+  gem 'combustion', '~> 0.9.0'
+
+  gem "rails", "~> 5.2.0"
+  gem "pg", "~> 1.0"
+end
+
+appraise "rails-edge-6" do
+  # Edge rails needs unreleased combustion
+  # https://github.com/pat/combustion/issues/92
+  gem 'combustion', git: "https://github.com/pat/combustion.git"
+
+  gem "rails", git: "https://github.com/rails/rails.git", branch: "master"
+  gem "pg", "~> 1.0"
+
+  # We don't actually use coffeescript at all, we need coffee-rails as an explicit
+  # dependency just for transitory edge weirdness using current sprockets release
+  # with rails 6 edge.
+  gem 'coffee-rails'
+end

Gemfile

@@ -3,40 +3,36 @@ source 'https://rubygems.org'
 # Specify your gem's dependencies in attr_json.gemspec
 gemspec
 
-# for our integration test in a real rails env, we add em in development too,
-# so we can bring up the app or a console in development to play with it.
-group :test, :development do
-  gem 'combustion', '~> 0.9.0'
-  # all of rails is NOT a dependency, just activerecord.
-  # But we use it for integration testing with combustion. Hmm, a bit annoying
-  # that now our other tests can't be sure they're depending, this might not
-  # be the way to do it.
-  gem "rails", ENV["RAILS_GEM"] && ENV["RAILS_GEM"].split(",")
-
-  # Rails 5.0 won't work with pg 1.0, but that isn't actually in it's gemspec.
-  # So we specify a compatible PG_GEM spec when testing with rails 5.
-  ENV['PG_GEM'] ||= ">= 0.18.1"
-  gem "pg", ENV['PG_GEM']
-
-  gem "rspec-rails", "~> 3.7"
-  gem "simple_form", ">= 4.0"
-  gem 'cocoon', ">= 1.2"
-  gem 'jquery-rails'
-  gem 'capybara', "~> 3.0"
-  gem "chromedriver-helper"
-  gem "selenium-webdriver"
-  # rails 5.1+ includes it by default, but rails 5.0 needs it:
-  gem 'rails-ujs', require: false
-end
-
-if ENV['RAILS_GEM']
-  gem "activerecord", ENV['RAILS_GEM'].split(",")
-
-  # This shouldn't really be needed, but seems to maybe be a bundler bug,
-  # this makes standalone_migrations dependencies resolve properly even when our
-  # RAILS_REQ is for 5.2.0.rc2. If in the future you delete this and everything
-  # still passes, feel free to remove.
-  gem "railties", ENV['RAILS_GEM'].split(",")
-end
+# Dependencies for testing and development. To let appraisal override them, we
+# do NOT put them in group :test,:development -- which anyway doesn't make a
+# lot of sense in a gem Gemfile anyway, there is no "production" in a gem Gemfile.
+#
+# We also have these development dependencies here in the Gemfile instead of the
+# gemspec so appraisal can override them from our Appraisal file.
+
+gem 'combustion', '~> 0.9.0'
+
+# all of rails is NOT a dependency, just activerecord.
+# But we use it for integration testing with combustion. Hmm, a bit annoying
+# that now our other tests can't be sure they're depending, this might not
+# be the way to do it.
+gem 'rails'
+
+# We should not really need to mention railties, it's already a dependency of
+# rails, but seems to be necessary to get around some mystery bug in bundler
+# dependency resolution.
+gem 'railties'
+
+gem "pg"
+gem "rspec-rails", "~> 3.7"
+gem "simple_form", ">= 4.0"
+gem 'cocoon', ">= 1.2"
+gem 'jquery-rails'
+
+gem 'capybara', "~> 3.0"
+gem "chromedriver-helper"
+gem "selenium-webdriver"
 
 gem "byebug"
+
+

README.md

@@ -424,6 +424,8 @@ At present this does mean that all our automated tests are run in a full Rails e
 
 Tests are in rspec, run tests simply with `./bin/rspec`.
 
+We use [appraisal](https://github.com/thoughtbot/appraisal) to test with multiple rails versions, including on travis. Locally you can run `bundle exec appraisal rspec` to run tests multiple times for each rails version, or eg `bundle exec appraisal rails-5-1 rspec`. If the `Gemfile` _or_ `Appraisal` file changes, you may need to re-run `bundle exec appraisal install` and commit changes. (Try to put dev dependencies in gemspec instead of Gemfile, but sometimes it gets weird.)
+
 There is a `./bin/console` that will give you a console in the context of attr_json and all it's dependencies, including the combustion rails app, and the models defined there.
 
 ## Acknowledements and Prior Art

attr_json.gemspec

@@ -42,11 +42,16 @@ attributes use as much of the existing ActiveRecord architecture as we can.}
 
   spec.required_ruby_version = '>= 2.4.0'
 
-  spec.add_runtime_dependency "activerecord", ">= 5.0.0", "< 5.3"
+  # Only to get CI to work on versions of Rails other than we release with,
+  # should never release a gem with RAILS_GEM set!
+  unless ENV['APPRAISAL_INITIALIZED'] || ENV["TRAVIS"]
+    spec.add_runtime_dependency "activerecord", ">= 5.0.0", "< 5.3"
+  end
 
   spec.add_development_dependency "bundler", "~> 1.14"
   spec.add_development_dependency "rake", ">= 10.0"
   spec.add_development_dependency "rspec", "~> 3.7"
   spec.add_development_dependency "database_cleaner", "~> 1.5"
   spec.add_development_dependency "yard-activesupport-concern"
+  spec.add_development_dependency "appraisal", "~> 2.2"
 end

gemfiles/.bundle/config

@@ -0,0 +1,2 @@
+---
+BUNDLE_RETRY: "1"

gemfiles/rails_5_0.gemfile

@@ -0,0 +1,19 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "combustion", "~> 0.9.0"
+gem "rails", "~> 5.0.0"
+gem "railties"
+gem "pg", "~> 0.18"
+gem "rspec-rails", "~> 3.7"
+gem "simple_form", ">= 4.0"
+gem "cocoon", ">= 1.2"
+gem "jquery-rails"
+gem "capybara", "~> 3.0"
+gem "chromedriver-helper"
+gem "selenium-webdriver"
+gem "byebug"
+gem "rails-ujs", require: false
+
+gemspec path: "../"

gemfiles/rails_5_1.gemfile

@@ -0,0 +1,18 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "combustion", "~> 0.9.0"
+gem "rails", "~> 5.1.0"
+gem "railties"
+gem "pg", "~> 1.0"
+gem "rspec-rails", "~> 3.7"
+gem "simple_form", ">= 4.0"
+gem "cocoon", ">= 1.2"
+gem "jquery-rails"
+gem "capybara", "~> 3.0"
+gem "chromedriver-helper"
+gem "selenium-webdriver"
+gem "byebug"
+
+gemspec path: "../"

gemfiles/rails_5_2.gemfile

@@ -0,0 +1,18 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "combustion", "~> 0.9.0"
+gem "rails", "~> 5.2.0"
+gem "railties"
+gem "pg", "~> 1.0"
+gem "rspec-rails", "~> 3.7"
+gem "simple_form", ">= 4.0"
+gem "cocoon", ">= 1.2"
+gem "jquery-rails"
+gem "capybara", "~> 3.0"
+gem "chromedriver-helper"
+gem "selenium-webdriver"
+gem "byebug"
+
+gemspec path: "../"

gemfiles/rails_edge_6.gemfile

@@ -0,0 +1,19 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "combustion", git: "https://github.com/pat/combustion.git"
+gem "rails", git: "https://github.com/rails/rails.git", branch: "master"
+gem "railties"
+gem "pg", "~> 1.0"
+gem "rspec-rails", "~> 3.7"
+gem "simple_form", ">= 4.0"
+gem "cocoon", ">= 1.2"
+gem "jquery-rails"
+gem "capybara", "~> 3.0"
+gem "chromedriver-helper"
+gem "selenium-webdriver"
+gem "byebug"
+gem "coffee-rails"
+
+gemspec path: "../"