How to understand "rake db:seed"

Question

I am using Michael Hartl's rails tutorials. Whenever I use the following

$ bundle exec rake db:migrate:reset 

Then

$ bundle exec rake db:seed

It waits. It doesn't show anything.

And when I do:

bundle exec rake test

I get

ActiveRecord::PendingMigrationError: Migrations are pending.
To resolve this issue, 
bin/rake db:migrate RAILS_ENV=test

When the above is done-"db:migrate RAILS_ENV=test", tests are clear.

However Michael doesn't mention anything happening about this scenario, Can anybody help and explain?

Answer 1

By default, most rake commands are going to run in the context of the RAILS_ENV passed to the command line. If no RAILS_ENV is passed to the command line, it will run in the development context, which is separate from the test context. There are a few exceptions, like rake db:create, which will create your development and test databases, but migrate will work against the specified environment.