module Shoulda::InstanceMethods

def get_instance_of(object_or_klass) # :nodoc:

:nodoc: 
def get_instance_of(object_or_klass) # :nodoc:
  if object_or_klass.is_a?(Class)
    klass = object_or_klass
    ivar = "@#{instance_variable_name_for(klass)}"
    if instance = instance_variable_get(ivar)
      warn "[WARNING] Using #{ivar} as the subject. Future versions " <<
           "of Shoulda will require an explicit subject using the " <<
           "subject class method. Add this after your setup to avoid " <<
           "this warning: subject { #{ivar} }"
      instance
    else
      klass.new
    end
  else
    object_or_klass
  end
end

def instance_variable_name_for(klass) # :nodoc:

:nodoc: 
def instance_variable_name_for(klass) # :nodoc:
  klass.to_s.split('::').last.underscore
end

def subject

being tested.
The subject is used by all macros that require an instance of the class

end
end
assert_equal @user, subject # passes
@user = User.new
should "be the existing user" do
class UserTest

class method.
recommended approach for using a different subject is to use the subject
deprecated, and will be removed in a future version of Shoulda. The
instance variable will be used as the subject. This behavior is
If an instance variable exists named after the described class, that

end
end
assert !subject.new_record? # uses the first user
should "be an existing user" do
subject { User.first }
class UserTest

The subject can be explicitly set using the subject class method:

end
end
assert_kind_of User, subject # passes
should "be a user" do
class UserTest

Returns an instance of the class under test. 
def subject
  if subject_block
    instance_eval(&subject_block)
  else
    get_instance_of(self.class.described_type)
  end
end

def subject_block # :nodoc:

:nodoc: 
def subject_block # :nodoc:
  (@shoulda_context && @shoulda_context.subject_block) || self.class.subject_block
end