What do we mean by this code if written in Gemfile

If I write the following code for example in 'Gemfile':

group :development do
gem 'xyz'
end

group:test do
gem 'xyz'
end

What do开发者_开发百科es that mean?

Thanks.

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You can specify which gems should be installed in which environment. For example, you might wanna use SQLite for development and testing, but MySQL on production. So you would write:

gem 'devise'

group :development, :test do
  gem 'sqlite'
end

group :production do
  gem 'mysql2'
end

Running bundle install --without development:test will install devise and mysql2 gems.

---

Only install the xyz gem in the development and test environments.

It can also be written as:

group :development, :test do
  gem 'xyz'
end

---

It means that all those gems in blocks will be loaded only in this environmets (test or development)