I write tests using Minitest and routinely reference EvilMartians System of a Test blog post for best practices for system tests. In this blog post, they also have an opinionated way of setting up System Tests.
EvilSystems offers 3 distinct advantages over the setup provided by
EvilMartians System of a Test:
1.) The blog post was built with RSpec in mind, but we use Minitest here!
2.) Constantly copying 5 files over into every new Rails app is annoying. Lets make that easier!
3.) File changes can end up out of sync, a gem makes sure updates can be pushed to all users.
EvilSystems is a quick, easy, reusable way to apply the SoaT concepts and settings
to projects for system tests using Minitest.
Full API documentation can be found here:
bundle add evil_systems --group=test
Make sure the following 3 gems are in your
Gemfile as well:
# Gemfile group :test do gem 'capybara' gem 'cuprite' # Optional gem 'selenium-webdriver' # Not required if using Cuprite and using Rails >= 6.1 end
bundle addby default appends the gem to the bottom of your
Gemfile, which means not in the
testgroup of gems. If the
capybaragem is in the
evil_systemsis not, you will not be able to load your application in production. Be sure that
evil_systemsis placed in the same group as
capybara(we recommend the
test/application_system_test_case.rb in your Rails app.
Setup your file like so:
# test/application_system_test_case.rb require 'test_helper' # 'capybara' and 'capybara/cuprite' need to be defined for EvilSystems to work properly. require 'capybara' require 'capybara/cuprite' require 'evil_systems' . class ApplicationSystemTestCase < ActionDispatch::SystemTestCase driven_by :evil_cuprite include :: end
Maybe in the future?
EvilSystems.initial_setup takes three keyword arguments,
They all have to do with precompiling assets.
:silent by default is set to
true and will only tell you when assets
are compiling, and how long the compilation took.
:task defaults to
assets:precompile, System of a test uses
true says you dont want to run any Rake tasks. Default is
EvilSystems.initial_setup(task: "webpacker:compile", silent: false)
[x] - Automatically registers a
[x] - Automatically sets
How `app_host` is set`app_host` will first use `ENV["APP_HOST"]` then falls back to the systems `hostname` if the `APP_HOST` ENV var is not defined. If neither are defined, it will then default to `"0.0.0.0"`
Capybara.server_host = "0.0.0.0"Make server listening on all hosts
Capybara.default_max_wait_time = 2Dont spend forever waiting for matchers
Capybara.default_normalize_ws = truenormalizes whitespace in
has_text?and similar matchers.
[x] - Sets the
ENV["CAPYBARA_ARTIFACTS"]and falls back to
[x] - Sets a
REMOTE_CHROMEinstance if a
[x] - Prepends a
last_used_sessionattribute accessor to Capybara.
ActionView::RecordIdentifier if Rails is
# The full path to be prepended to a screen shot absolute_image_path # The relative path to be prepended to a screenshot message to make it clickable image_path # Make failure screenshots compatible with multi-session setup take_screenshot # Prepends a '#' to the +dom_id+ method provided by Rails dom_id(*args)
# Small wrapper around Capybara.using_session thats easy to call from an instance within_session(name_or_session, &block)
# pauses the page pause # Opens a Pry or IRB repl. Will use Pry if Pry is defined, fallsback # to debugging with IRB debug binding # waits to make sure theres no active connections. wait_for_network_idle!
ENV variables used by this gem.
ENV["APP_HOST"] # used for Capybara.app_host ENV["CAPYBARA_ARTIFACTS"] # used for Capybara.save_path ENV["CHROME_URL"] # used for setting a remote chrome instance for Cuprite ENV["PROCESS_TIMEOUT"] # How long to wait before killing the process, default is 5 seconds ENV["CI"] # Whether or not to run Cuprite in headless mode, defaults to true. ENV["SLOWMO"] # Delay in seconds before sending a command (default 0). Also see https://github.com/rubycdp/ferrum#customization ENV["DISABLE_ANIMATION"] # Configure whether Capybara should render animations, default is true
I don't want to use Cuprite.
Thats fine! I totally get it. Selenium is battle tested. Simply remove
require "capybara/cuprite" line and
EvilSystems will detect that
Cuprite is not defined and not setup a driver for you and not include
Omissions and differences
webpacker:compilebefore systems tests (configurable)
Does not set the
Rails.application.default_url_options[:host]due to parallelization issues found while testing the dummy app.
The gem is available as open source under the terms of the MIT License.