Rails & RSpec: test DB with preexisting records - mysql

Question

All my previous projects used DatabaseCleaner, so I'm used to starting with an empty DB and creating test data within each test with FactoryGirl.
Currently, I'm working on a project that has a test database with many records. It is an sql file that all developers must import in their local test environments. The same DB is imported in the continuous integration server. I feel like having less control over the test data makes the testing process harder.
Some features allow their tests to focus on specific data, such as records that are associated to a certain user. In those cases, the preexisting data is irrelevant. Other features such as a report that displays projects of all clients do not allow me to "ignore" the preexisting data.
Is there any way to ignore the test DB contents in some tests (emulate an empty DB and create my own test data without actually deleting all rows in the test DB)? Maybe have two databases (both in the same MySQL server) and being able to switch between them (e.g., some tests use one DB, other tests use the other DB)?
Any other recommendations on how deal with to this scenario?
Thank you.

Answer 1

I would recommend preserving your test_database, and the 'test' environment as your 'clean' state. Then you could setup a separate database that you initially seed as your 'dirty' database. A before hook in your rails_helper file could also be setup with something like this:
RSpec.configure do |config|
config.before :each, type: :feature do |example|
if ENV['TEST_DIRTY'] || example.metadata[:test_dirty]
ActiveRecord::Base.establish_connection(
{
:adapter => 'mysql2',
:database => 'test_dirty',
:host => '127.0.0.1',
:username => 'root',
:password => 'password'
}
)
end
end
end
Your database.yml file will need configurations added for your 'dirty' database. But I think the key here is keeping your clean and dirty states separate. Cheers!

Answer 2

I have found that adding the following configuration to spec/rails_helper.rb will run all DB operations inside tests or before(:each) blocks as transactions, which are rolled back after each test is finished. That means we can do something like before(:each) { MyModel.delete_all }, create our own test data, run our assertions (which will only see the data we created) and after the end of the test, all preexisting data will still be in the DB because the deletion will be rolled back.
RSpec.configure do |config|
config.use_transactional_fixtures = true
end