# Use Sorbet compatible setup-initializations in tests

Sorbet can help with type inference in tests if the setup is right. Otherwise types will be reduced to `T.untyped`.

## Don't do

```ruby
class Test < ActiveSupport::TestCase
  def setup # Don't use `dev setup`.
    @user = make_fixture(User, :alex) # Don't forget `T.let`
  end
end
```

## Do

```ruby
class Test < ActiveSupport::TestCase
  setup do
    @user = T.let(make_fixture(User, :alex), User)
  end
end
```

With this latter `@user` will be infered as type `User`, and it does not need to be nilable.