How to clean DB with Rails 5, Minitest, Capybara JS (Selenium)? - selenium

Question

I have set up a very simple rails 5 project to narrow down my problem:
https://github.com/benedikt-voigt/capybara_js_demo
In this project the data mutation done by the Capybara JS is not deleted, neither by Rails nor by the Database cleaner I added.
The following great blog argues, that no DatabaseCleaner is needed:
http://brandonhilkert.com/blog/7-reasons-why-im-sticking-with-minitest-and-fixtures-in-rails
but this works only for fixtures, not for the mutation done by an out-of-thread Capybara test.
I added the Database cleaner, but this also needed work.
Does anybody has a sample setup?

Answer 1

From a quick look at your test I would say it's leaving data because the data is actually being added after DatabaseCleaner cleans. The click_on call occurs asynchronously, so when your assert_no_content call happens there's no guarantee the app has handled the request yet or the page has changed yet and since the current page doesn't have the text 'Name has already been taken' on it the assertion passes and the database gets cleaned. While that is happening the click gets processed by the app and the new data is created after the cleaning has occurred. You need to check/wait for content that will appear on the page after the click - something like
page.assert_text('New Foo Created')
You should only be asserting there is no content once you already know the page has changed, or you're expecting something to disappear from the current page.

Answer 2

I solved now the problem by setting the DB connection to one
class ActiveRecord::Base
mattr_accessor :shared_connection
##shared_connection = nil
def self.connection
##shared_connection || ConnectionPool::Wrapper.new(:size => 1) { retrieve_connection }
end
end
ActiveRecord::Base.shared_connection = ActiveRecord::Base.connection
as describe here:
https://mattbrictson.com/minitest-and-rails
I uploaded the working repo here:
https://github.com/benedikt-voigt/capybara_js_demo_working