104 lines
4.2 KiB
Common Lisp
104 lines
4.2 KiB
Common Lisp
(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 (call 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 (call 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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(call compounder :move-forward-years 83)
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(assert= 1000 (call 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 (call 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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(call compounder :move-forward-years 1)
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(assert= 105000 (call 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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(call compounder :move-forward-years 2)
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(assert= 110250 (call 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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(call compounder :move-forward-years 3)
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(assert= 115763 (call 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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(call compounder :move-forward-years 4)
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(assert= 121551 (call 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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(call compounder :move-forward-years 1)
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(assert= 95000 (call 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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(call compounder :move-forward-years 2)
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(assert= 90250 (call 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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(call compounder :move-forward-years 3)
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(assert= 85737 (call 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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(call compounder :move-forward-years 4)
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(assert= 81450 (call 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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(call compounder :move-forward-years -4)
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(assert= 100000 (call compounder :get-principal))
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(call compounder :move-forward-years 1)
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(call compounder :move-forward-years -4)
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(assert= 105000 (call 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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(call compounder :move-forward-years 0)
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(assert= 100000 (call compounder :get-principal))
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(call compounder :move-forward-years 1)
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(call compounder :move-forward-years 0)
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(assert= 105000 (call compounder :get-principal)))
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(defun variable-interest-rate ()
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(setf compounder (interest-compounder 100000 5))
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(call compounder :move-forward-years 2)
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(call compounder :set-interest-rate 10)
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(call compounder :move-forward-years 2)
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(assert= 133403 (call compounder :get-principal)))
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(defun years-are-updated ()
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(setf compounder (interest-compounder 100000 5))
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(call compounder :move-forward-years 27)
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(assert= 27 (call compounder :get-years-passed)))
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(defun negative-number-of-years-does-not-update-years ()
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(setf compounder (interest-compounder 100000 5))
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(call compounder :move-forward-years 27)
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(call compounder :move-forward-years -2)
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(assert= 27 (call compounder :get-years-passed)))
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(defun zero-number-of-years-does-not-update-years ()
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(setf compounder (interest-compounder 100000 5))
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(call compounder :move-forward-years 27)
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(call compounder :move-forward-years 0)
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(assert= 27 (call compounder :get-years-passed))))))
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