class Shoulda::Matchers::ActiveRecord::ValidateUniquenessOfMatcher::ExistingRecordInvalid

def message
  <<-MESSAGE.strip
niqueness_of works by matching a new record against an
ecord. If there is no existing record, it will create one
record you provide.
g this, the following error was raised:
:Matchers::Util.indent(underlying_exception.message, 2)}
ay to fix this is to provide the matcher with a record where
ed attributes are filled in with valid values beforehand.
  MESSAGE
end