How to set up test database configuration in Rails - ruby-on-rails

Question

I am working on existing rails project and just finished writing some basic RSpec tests for that.
In our database.yml file we have connection to 3-4 different databases and all are either pointing to either production database or staging database.
For testing environment I created a different yml file called database.test.yml and then symlinked it to database.yml file, so that the correct testing databases connections are created.
My database.test.yml looks something like this:
abc:
adapter: mysql2
host: localhost
reconnect: true
username: monty
password: python
database: abc
pqr:
adapter: mysql2
host: localhost
reconnect: true
username: monty
password: python
database: pqr
test:
adapter: mysql2
host: localhost
reconnect: true
username: monty
password: python
pool: 50
database: testing
My problem now is that how can I enforce that other developers/testers use this database.test.yml and not accidentally run the main database.yml file which contains connections to staging and production databases.
EDIT:
To further clarify my question, I have establish_connection in various models that connect to different databases. So I am not sure the earlier suggestions will solve my problem.
Example:
class Abc < ActiveRecord::Base
establish_connection :abc
end
One way I can think of for solving my problem is doing something like this:
class Abc < ActiveRecord::Base
establish_connection "abc_#{Rails.env}"
end
and in the database.yml:
defaults: &defaults
adapter: mysql2
encoding: utf8
username: root
password: secret
abc_production:
database: abc
<<: *defaults
abc_development:
database: abc_devlopment
<<: *defaults
abc_test:
database: abc_test
<<: *defaults
But I am not sure if this the best practice and I really don't feel to change the application code to setup test environment is good practice.
This idea is based on: http://blog.nistu.de/2012/03/25/multi-database-setup-with-rails-and-rspec
Any nudge or pointers towards the correction direction will be greatly helpful.

Answer 1

You could have something, like:
default: &default
adapter: mysql2
encoding: utf8
database: my_db_name
username: root
password: my_password
host: 127.0.0.1
port: 3306
development:
<<: *default
database: xxxx_development
# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
<<: *default
database: xxxx_test
production:
<<: *default
database: xxxx_production