Appraisal
Find out what your Ruby gems are worth.
Synopsis
Appraisal integrates with bundler and rake to test your library against different versions of dependencies in repeatable scenarios called "appraisals." Appraisal is designed to make it easy to check for regressions in your library without interfering with day-to-day development using Bundler.
Installation
In your package's .gemspec
:
s.add_development_dependency "appraisal"
Note that gems must be bundled in the global namespace. Bundling gems to a local location or vendoring plugins is not supported. If you do not want to pollute the global namespace, one alternative is RVM's Gemsets.
Setup
Setting up appraisal requires an Appraisals
file (similar to a Gemfile
) in
your project root, named "Appraisals" (note the case), and some slight changes
to your project's Rakefile
.
An Appraisals
file consists of several appraisal definitions. An appraisal
definition is simply a list of gem dependencies. For example, to test with a
few versions of Rails:
appraise "rails-3" do
gem "rails", "3.2.14"
end
appraise "rails-4" do
gem "rails", "4.0.0"
end
The dependencies in your Appraisals
file are combined with dependencies in
your Gemfile
, so you don't need to repeat anything that's the same for each
appraisal. If something is specified in both the Gemfile and an appraisal, the
version from the appraisal takes precedence.
Usage
Once you've configured the appraisals you want to use, you need to install the dependencies for each appraisal:
$ bundle exec appraisal install
This will resolve, install, and lock the dependencies for that appraisal using bundler. Once you have your dependencies set up, you can run any command in a single appraisal:
$ bundle exec appraisal rails-3 rake test
This will run rake test
using the dependencies configured for Rails 3. You can
also run each appraisal in turn:
$ bundle exec appraisal rake test
If you want to use only the dependencies from your Gemfile, just run rake
test
as normal. This allows you to keep running with the latest versions of
your dependencies in quick test runs, but keep running the tests in older
versions to check for regressions.
In the case that you want to run all the appraisals by default when you run
rake
, you can override your default Rake task by put this into your Rakefile:
if !ENV["APPRAISAL_INITIALIZED"] && !ENV["TRAVIS"]
task :default => :appraisal
end
(Appraisal sets APPRAISAL_INITIALIZED
environment variable when it runs your
process. We put a check here to ensure that appraisal rake
command should run
your real default task, which usually is your test
task.)
Note that this may conflict with your CI setup if you decide to split the test
into multiple processes by Appraisal and you are using rake
to run tests by
default.
Commands
appraisal clean # Remove all generated gemfiles and lockfiles from gemfiles folder
appraisal generate # Generate a gemfile for each appraisal
appraisal help [COMMAND] # Describe available commands or one specific command
appraisal install # Resolve and install dependencies for each appraisal
appraisal list # List the names of the defined appraisals
appraisal update [LIST_OF_GEMS] # Remove all generated gemfiles and lockfiles, resolve, and install dependencies again
appraisal version # Display the version and exit
Under the hood
Running appraisal install
generates a Gemfile for each appraisal by combining
your root Gemfile with the specific requirements for each appraisal. These are
stored in the gemfiles
directory, and should be added to version control to
ensure that the same versions are always used.
When you prefix a command with appraisal
, the command is run with the
appropriate Gemfile for that appraisal, ensuring the correct dependencies
are used.
Removing Gems using Appraisal
It is common while managing multiple Gemfiles for dependencies to become deprecated and no
longer necessary, meaning they need to be removed from the Gemfile for a specific appraisal
.
To do this, use the remove_gem
declaration within the necessary appraise
block in your
Appraisals
file.
Example Usage
Gemfile
gem 'rails', '~> 4.2'
group :test do
gem 'rspec', '~> 4.0'
gem 'test_after_commit'
end
Appraisals
appraise 'rails-5' do
gem 'rails', '~> 5.2'
group :test do
remove_gem 'test_after_commit'
end
end
Using the Appraisals
file defined above, this is what the resulting Gemfile
will look like:
gem 'rails', '~> 5.2'
group :test do
gem 'rspec', '~> 4.0'
end
Customization
It is possible to customize the generated Gemfiles by adding a customize_gemfiles
block to
your Appraisals
file. The block must contain a hash of key/value pairs. Currently supported
customizations include:
- heading: a string that by default adds "# This file was generated by Appraisal" to the top of each Gemfile, (the string will be commented for you)
- single_quotes: a boolean that controls if strings are single quoted in each Gemfile, defaults to false
You can also provide variables for substitution in the heading, based on each appraisal. Currently supported variables:
%{appraisal}
: Becomes the name of each appraisal, e.g.rails-3
%{gemfile}
: Becomes the filename of each gemfile, e.g.rails-3.gemfile
%{gemfile_path}
: Becomes the full path of each gemfile, e.g./path/to/project/gemfiles/rails-3.gemfile
%{lockfile}
: Becomes the filename of each lockfile, e.g.rails-3.gemfile.lock
%{lockfile_path}
: Becomes the full path of each lockfile, e.g./path/to/project/gemfiles/rails-3.gemfile.lock
%{relative_gemfile_path}
: Becomes the relative path of each gemfile, e.g.gemfiles/rails-3.gemfile
%{relative_lockfile_path}
: Becomes the relative path of each lockfile, e.g.gemfiles/rails-3.gemfile.lock
Example Usage
Appraisals
customize_gemfiles do
{
single_quotes: true,
heading: <<~HEADING
frozen_string_literal: true
`%{gemfile}` has been generated by Appraisal, do NOT modify it or `%{lockfile}` directly!
Make the changes to the "%{appraisal}" block in `Appraisals` instead. See the conventions at https://example.com/
HEADING
}
end
appraise "rails-3" do
gem "rails", "3.2.14"
end
Using the Appraisals
file defined above, this is what the resulting Gemfile
will look like:
# frozen_string_literal: true
# `rails-3.gemfile` has been generated by Appraisal, do NOT modify it or `rails-3.gemfile.lock` directly!
# Make the changes to the "rails-3" block in `Appraisals` instead. See the conventions at https://example.com/
gem 'rails', '3.2.14'
Version Control
When using Appraisal, we recommend you check in the Gemfiles that Appraisal
generates within the gemfiles directory, but exclude the lockfiles there
(*.gemfile.lock
.) The Gemfiles are useful when running your tests against a
continuous integration server.
Circle CI Integration
In Circle CI you can override the default testing behaviour to customize your testing. Using this feature you can configure appraisal to execute your tests.
In order to this you can put the following configuration in your circle.yml file:
dependencies:
post:
- bundle exec appraisal install
test:
pre:
- bundle exec appraisal rake db:create
- bundle exec appraisal rake db:migrate
override:
- bundle exec appraisal rspec
Notice that we are running an rspec suite. You can customize your testing
command in the override
section and use your favourite one.
Credits
Appraisal is maintained and funded by thoughtbot, inc
Thank you to all the contributors
The names and logos for thoughtbot are trademarks of thoughtbot, inc.
License
Appraisal is Copyright © 2010-2013 Joe Ferris and thoughtbot, inc. It is free software, and may be redistributed under the terms specified in the MIT-LICENSE file.