def reciever_name
    params['VK_REC_NAME']
  end

  def reciever_bank_account
    params['VK_REC_ACC']
  end

Please change from reciever* to receiver*

➜ banklink git:(master) rake
/Users/sac/.rvm/rubies/ruby-2.0.0-p451/bin/ruby -I"lib:lib:test" -I"/Users/sac/.rvm/gems/ruby-2.0.0-p451/gems/rake-10.1.1/lib" "/Users/sac/.rvm/gems/ruby-2.0.0-p451/gems/rake-10.1.1/lib/rake/rake_test_loader.rb" "test/*_/__test.rb"
Run options:

Running tests:

[ 4/12] BanklinkNotificationTest#test_accessors = 0.00 s

1. Error:
   BanklinkNotificationTest#test_accessors:
   NoMethodError: undefined method civil' for Date:Class /Users/sac/banklink/lib/banklink/swedbank/notification.rb:102:inreceived_at'
   /Users/sac/banklink/test/banklink_notification_test.rb:24:in `test_accessors'

Finished tests in 0.034493s, 347.8967 tests/s, 579.8278 assertions/s.
12 tests, 20 assertions, 0 failures, 1 errors, 0 skips

ruby -v: ruby 2.0.0p451 (2014-02-24 revision 45167) [x86_64-darwin13.0.0]
rake aborted!
Command failed with status (1): [ruby -I"lib:lib:test" -I"/Users/sac/.rvm/gems/ruby-2.0.0-p451/gems/rake-10.1.1/lib" "/Users/sac/.rvm/gems/ruby-2.0.0-p451/gems/rake-10.1.1/lib/rake/rake_test_loader.rb" "test/*_/__test.rb" ]
/Users/sac/.rvm/gems/ruby-2.0.0-p451/bin/ruby_executable_hooks:15:in eval' /Users/sac/.rvm/gems/ruby-2.0.0-p451/bin/ruby_executable_hooks:15:in

Loading development environment (Rails 4.0.0)
SETTING
:001 > Banklink::Swedbank.service_url = "/tram/tram/ta/ram/"
=> "/tram/tram/ta/ram/"
GETTING
:002 > Banklink::Swedbank.service_url
SystemStackError: stack level too deep
from /Users/sac/.rvm/rubies/ruby-2.0.0-p451/lib/ruby/2.0.0/irb/workspace.rb:86
Maybe IRB bug!

Same story when running server