Compare state directly in specs.
Compare state directly in specs.

Previously this test used the invalid? method definition from state
machine which conflicted with a method from ActiveModel. Instead of
dealing with that issue, we will compare the state directly to what it
should be rather than relying upon the magic methods defined by
state_machine.

Fixes #5

madetech/spree_store_credit_payment_method,madetech/spree_store_credit_payment_method,forvalho/spree_gift_cards,mleglise/spree_store_credit_payment_method,bryanmtl/spree_store_credit_payment_method,DynamoMTL/spree_store_credit_payment_method,madetech/spree_gift_cards,reinaris/spree_gift_cards,madetech/spree_gift_cards,DynamoMTL/spree_store_credit_payment_method,RatioClothing/spree_store_credit_payment_method,spree-contrib/spree_store_credit_payment_method,bryanmtl/spree_store_credit_payment_method,surfdome/spree_gift_cards,TechFlavor/spree_store_credit_payment_method,bryanmtl/spree_store_credit_payment_method,surfdome/spree_gift_cards,RatioClothing/spree_store_credit_payment_method,forvalho/spree_gift_cards,surfdome/spree_gift_cards,mleglise/spree_store_credit_payment_method,madetech/spree_gift_cards,TechFlavor/spree_store_credit_payment_method,reinaris/spree_gift_cards,madetech/spree_store_credit_payment_method,spree-contrib/spree_store_credit_payment_method,reinaris/spree_gift_cards,TechFlavor/spree_store_credit_payment_method,RatioClothing/spree_store_credit_payment_method