How to specify which database we're using?

I am seeding my environment for testing, but I am doing it upon my
development environment, and in fact I'd like to seed my test

How can I do that?

rake db:seed RAILS_ENV=test


rake db:seed RAILS_ENV=test

Will that work? I realise that it will seed the test db but I thought
that test db was cleared and refilled from fixtures for each test.