rails4 - Psych::BadAlias: Unknown alias: test - ruby-on-rails

Question

trying to deploy my project using Capistrano cap deploy:migrate , I get an error in my database.yml on the test alias ( which is just running fine on local server)
development:
database: db_dev
adapter: mysql2
username: xxxxxx
password: xxxxxx
host: localhost
encoding: utf8
test: &test
database: db_test
adapter: mysql2
username: xxxxxx
password: xxxxxx
host: localhost
encoding: utf8
production:
database: db_prod
adapter: mysql2
username: xxxxxxxx
password: xxxxxxx
host: localhost
encoding: utf8
cucumber:
<<: *test
the console log is :
rake aborted!
Psych::BadAlias: Unknown alias: test
/railties-4.0.3/lib/rails/application/configuration.rb:106:in `database_configuration'
/activerecord-4.0.3/lib/active_record/railtie.rb:175:in `block (2 levels) in <class:Railtie>'
/activesupport-4.0.3/lib/active_support/lazy_load_hooks.rb:38:in `instance_eval'
/activesupport-4.0.3/lib/active_support/lazy_load_hooks.rb:38:in `execute_hook'
/activesupport-4.0.3/lib/active_support/lazy_load_hooks.rb:28:in `block in on_load'
/activesupport-4.0.3/lib/active_support/lazy_load_hooks.rb:27:in `each'
/activesupport-4.0.3/lib/active_support/lazy_load_hooks.rb:27:in `on_load'
/activerecord-4.0.3/lib/active_record/railtie.rb:174:in `block in <class:Railtie>'
/railties-4.0.3/lib/rails/initializable.rb:30:in `instance_exec'
/railties-4.0.3/lib/rails/initializable.rb:30:in `run'
/railties-4.0.3/lib/rails/initializable.rb:55:in `block in run_initializers'
/railties-4.0.3/lib/rails/initializable.rb:54:in `run_initializers'
/railties-4.0.3/lib/rails/application.rb:215:in `initialize!'
/railties-4.0.3/lib/rails/railtie/configurable.rb:30:in `method_missing'
/home/kadoudal/rails/swim-tech.eu/site/swimtech/releases/20140326140458/config/environment.rb:6:in `<top (required)>'
/activesupport-4.0.3/lib/active_support/dependencies.rb:229:in `require'
/activesupport-4.0.3/lib/active_support/dependencies.rb:229:in `block in require'
/activesupport-4.0.3/lib/active_support/dependencies.rb:214:in `load_dependency'
/activesupport-4.0.3/lib/active_support/dependencies.rb:229:in `require'
/railties-4.0.3/lib/rails/application.rb:189:in `require_environment!'
/railties-4.0.3/lib/rails/application.rb:250:in `block in run_tasks_blocks'
Tasks: TOP => db:migrate => environment

Answer 1

You can avoid this problem by passing aliases: true argument to YAML.safe_load method:
YAML.safe_load(File.read('config/database.yml'), aliases: true)

Answer 2

I don't believe you can alias test, development, or production as they are assigned based on the environment you boot in (if environment is production, the production settings will be applied). The issue is that if this were to work, cucumber would only be usable in the test environment.
I used something akin to the below:
base: &base
adapter: mysql2
host: address.com
encoding: utf8
adapter: mysql2
username: xxxxxx
password: xxxxxx
development:
database: db_dev
<<: *base
test:
database: db_test
<<: *base
production:
database: db_prod
<<: *base
cucumber:
database: cucumber
<<: *base