temp2.rb

describe Stack do
  Invariants do
    If { stack.empty? }
    Then { stack.depth.should == 0 }
    Then { stack.should be_pushable }
    ElseIf { stack.full? }
    Then { stack.depth.should == stack.max_depth }
    Then { stack.should_not be_pushable }
    Else
    Then { stack.depth.should be > 0 } # not wild about this part

    # Alternative
    When { stack.empty? }
    # thens
    When { stack.full? }
    # thens
    Otherwise
    Then { stack.depth.should be > 0 } #not wild about this part
    # more thens
  end
end