simpletest.rb

def test_when_success_with_nothing_to_chain
    myObject = mock()     
    myObject.expects(:method).once.returns(nil)
    myObject.expects(:method_to_be_called).once
    When.success{myObject.method}.then_call{myObject.method_to_be_called}.as_a_chain
end

test_chaining.rb

def test_that_parameter_is_chained_when_as_a_chain_is_called
   parameter = 'Highly difficult to calculate value'
   myObject = mock()
   myObject.expects(:method).once.returns(parameter)
   myObject.expects(:method_to_be_called).with(parameter).once
   When.success{myObject.method}.then_call{|x| myObject.method_to_be_called(x)}.as_a_chain
end

test_overload.rb

def test_overload_of_that
    parameter = 'Highly difficult to calculate value'
    myObject = mock()
    myObject.expects(:method).once.returns(parameter)
    myObject.expects(:method_to_be_called).with(parameter).once
    When.success{myObject.method}.then_call(:as_a_chain){|x| myObject.method_to_be_called(x)}
end