write rate smoothing test (just rate test)
implement rate smoothing
change dummyrateconverterto to allow init with tuples of (date, rate) but not require
allow rate smoothing initial window size initialization
suppress mean of empty slice warning
Add test for dummy lookup rate expected
Refactor value error assertion, no return
implement obvious lookup rate expected
restore calculator tests
Add parametrized calculator tests WON'T IMPLEMENT
Move dummy converter smoothing rate to abstract converter
Add invalid date test
Fix double printing of invalid message
write main function
- write fake payment, rent to temp directory as csv