Add validation to line_item.rb

[ankit1910]

1. add order presence validation
2. fix ensure_proper_currency

[damianlegawiec]

@ankit1910

validate :ensure_proper_currency, if: -> { order.present? }

Why are we checking if order exists? All line items must be associated to order, after adding presence validation it isn't required to have this check.

[ankit1910]

@damianlegawiec : Thanks for your feedback.
In case when line items are not associated with order. and we call line_item.valid? on any object then it will raise an exception inside ensure_proper_currency method.

[damianlegawiec]

@ankit1910 you've added presence validation, so what's the purpose of even checking for order once again? Record won't be created if order doesn't exist.

[ankit1910]

Removing this condition will make system run validation ensure_proper_currency even in case when order is nil and this method will call currency on order that is nil at this time. This will raise an exception inside ensure_proper_currency.

NoMethodError:
undefined method `currency' for nil:NilClass

./app/models/spree/line_item.rb:153:in`ensure_proper_currency'

/Users/ankit/.rvm/gems/ruby-2.1.5/gems/activesupport-4.2.5.1/lib/active_support/callbacks. rb:432:in `block in make_lambda'

/Users/ankit/.rvm/gems/ruby-2.1.5/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:192:in`call'

/Users/ankit/.rvm/gems/ruby-2.1.5/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:192:in `block in simple'

/Users/ankit/.rvm/gems/ruby-2.1.5/gems/activesupport-4.2.5.1/lib/active_support/callbacks.rb:504:in`call'

[priyank-gupta]

@ankit1910 Agreed!!!
@damianlegawiec This seems fine.