Rails 5 - Unable to Cleanse Test DB - ruby-on-rails

Question

I've recently started testing my app using RSpec. Being the testing noob that i am, i did not install the full suite of tools that people normally use (namely FactoryGirl, also now known as FactoryBot. And DatabaseCleaner).
Anyway here's what happened. After getting my feet wet with RSpec, i started using FactoryBot so that my tests looks less convoluted. Note that :user is a Devise object.
# spec/models/first_test_spec.rb
FactoryBot.create(:user)
#Other Code
So i'm doing stuff with my first_test_spec.rb and i run it and everything is working perfectly fine. I then create my 2nd spec file
# spec/models/second_test_spec.rb
FactoryBot.create(:user)
#Other Code
Now here comes the problem. My tests are failing because FactoryBot.create(:user) is invalid, due to Devise requiring unique emails. Clearly this indicates that the data from my first_test_spec is persisting hence the error.
So i attempt to install DatabaseCleaner and hopefully clear my Test DB after each run. My rails_helper looks like this:
require 'spec_helper'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
abort("The Rails environment is running in production mode!") if Rails.env.production?
require 'rspec/rails'
require 'support/factory_bot'
# Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }
ActiveRecord::Migration.maintain_test_schema!
RSpec.configure do |config|
config.fixture_path = "#{::Rails.root}/spec/fixtures"
config.use_transactional_fixtures = false
config.before(:suite) do
DatabaseCleaner.clean_with(:truncation)
end
config.before(:each) do
DatabaseCleaner.strategy = :transaction
end
config.before(:each, js: true) do
DatabaseCleaner.strategy = :truncation
end
config.before(:each) do
DatabaseCleaner.start
end
config.after(:each) do
DatabaseCleaner.clean
end
config.infer_spec_type_from_file_location!
config.filter_rails_from_backtrace!
end
I think i've got everything set up correctly, so i'm uncertain if the errors are still occurring due to my DatabaseCleaner being set up wrongly.
Anyway, running rspec still throws the same error, where second_test_spec cannot create the user object because the email already exists (a validation that comes with Devise itself).
I then proceed to run the following:
rake db:test:prepare
rspec spec/models/second_test_spec.rb
And it still throws the same error. So right now, i have no idea if my database is being cleanse after running rspec. But i'm quite certain that i have been unable to purge my test database.
So i guess i really have 2 questions/problems:
1) How do you purge your test database? (Googling reveals that rake db:test:prepare is the way)
2) Is my DatabaseCleaner setup correctly? If so, shouldn't it be purging the database?
UPDATE:
As suggested to me in the comments, using sequence for creating unique fields with FactoryBot is recommended. Obviously that made the problem go away because there would no longer be validation errors from Devise.
I then went on to test a couple of things.
rails c test
I ran this to check my test database and it was indeed empty. This indicates that DatabaseCleaner is working perfectly fine. What i fail to understand then, is why the need to sequence my email creation in FactoryBot? Or i suppose, i fail to understand how does RSpec "compile & run".
puts #user.email
So i wanted to print out the emails to look at the sequencing to see if i'm able to decipher the problem. Here's what happens:
running rspec spec/models/first_test_spec.rb
Tutor email yields the number 2.
running rspec spec/models/second_test_spec.rb
Tutor email yields the number 3.
running rspec
Tutor email yields the numbers 2 & 5.
So i'm not sure if there are "problems" with my test suite. Clearly my original problem has been fixed, and this is a separate topic altogether. But i figured if anyone would like to explain this mystery to anyone else who chances upon this thread may wish to do so.

Answer 1

Seeing your full spec files would help. If you are running the specs as you've written - creating a user outside of an example group or a before block - that will cause records to be written outside of the cleaning strategy scope and can cause data to remain across examples. Your DBcleaner config looks to be set up fine otherwise.
rake db:test:prepare is the correct way to clean out your test db but shouldn't need to be ran often unless you have migration changes. You can jump into a rails console within the test environment rails c test and look around to see if there are any records left behind.
As a side note you can flip config.use_transactional_fixtures from false to true and remove DBcleaner altogether from your app. Just make sure there is no residual data in your database before going this route.