81 lines
3.4 KiB
Common Lisp
81 lines
3.4 KiB
Common Lisp
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(load "../unit/unit-test.lisp")
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(load "interest-compounder.lisp")
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(unit
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(let ((compounder))
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(list
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(defun principal-initialized ()
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(setf compounder (interest-compounder 1000 0))
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(assert= 1000 (funcall compounder :get-principal)))
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(defun interest-rate-initialized ()
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(setf compounder (interest-compounder 0 10))
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(assert= 10 (funcall compounder :get-interest-rate)))
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(defun many-years-with-no-interest-rate ()
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(setf compounder (interest-compounder 1000 0))
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(funcall compounder :move-forward-years 83)
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(assert= 1000 (funcall compounder :get-principal)))
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(defun no-years-with-positive-interest-rate ()
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(setf compounder (interest-compounder 1000 10))
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(assert= 1000 (funcall compounder :get-principal)))
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(defun one-year-with-positive-interest-rate ()
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(setf compounder (interest-compounder 100000 5))
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(funcall compounder :move-forward-one-year)
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(assert= 105000 (funcall compounder :get-principal)))
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(defun two-years-with-positive-interest-rate ()
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(setf compounder (interest-compounder 100000 5))
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(funcall compounder :move-forward-one-year)
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(funcall compounder :move-forward-one-year)
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(assert= 110250 (funcall compounder :get-principal)))
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(defun three-years-with-positive-interest-rate ()
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(setf compounder (interest-compounder 100000 5))
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(funcall compounder :move-forward-years 3)
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(assert= 115763 (funcall compounder :get-principal)))
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(defun four-years-with-positive-interest-rate ()
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(setf compounder (interest-compounder 100000 5))
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(funcall compounder :move-forward-years 4)
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(assert= 121551 (funcall compounder :get-principal)))
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(defun one-year-with-negative-interest-rate ()
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(setf compounder (interest-compounder 100000 -5))
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(funcall compounder :move-forward-years 1)
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(assert= 95000 (funcall compounder :get-principal)))
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(defun two-years-with-negative-interest-rate ()
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(setf compounder (interest-compounder 100000 -5))
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(funcall compounder :move-forward-years 2)
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(assert= 90250 (funcall compounder :get-principal)))
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(defun three-years-with-negative-interest-rate ()
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(setf compounder (interest-compounder 100000 -5))
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(funcall compounder :move-forward-years 3)
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(assert= 85737 (funcall compounder :get-principal)))
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(defun four-years-with-negative-interest-rate ()
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(setf compounder (interest-compounder 100000 -5))
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(funcall compounder :move-forward-years 4)
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(assert= 81450 (funcall compounder :get-principal)))
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(defun negative-number-of-years-does-nothing ()
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(setf compounder (interest-compounder 100000 5))
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(funcall compounder :move-forward-years -4)
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(assert= 100000 (funcall compounder :get-principal))
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(funcall compounder :move-forward-years 1)
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(funcall compounder :move-forward-years -4)
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(assert= 105000 (funcall compounder :get-principal)))
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(defun zero-number-of-years-does-nothing ()
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(setf compounder (interest-compounder 100000 5))
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(funcall compounder :move-forward-years 0)
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(assert= 100000 (funcall compounder :get-principal))
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(funcall compounder :move-forward-years 1)
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(funcall compounder :move-forward-years 0)
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(assert= 105000 (funcall compounder :get-principal))))))
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