Stock Out Days is 29 instead of 30

QA: After the recent changes, PASSED

• 31-days-months when there was no stock available returns 30 stock-out days (which is correct)

• 30-days-months when there was no stock available returns 30 stock-out days (which is correct)

• Making Receive in a 31-days-month period at 13th day and Issue at 19th day results in 24 stock-out days (which is correct)

• Making Receive in a 30-days-month period at 13th day and Issue at 19th day results in 24 stock-out days (which is correct)

• Full February is counted as 30 days (which is correct)

I’m moving the ticket to To Be Released status. cc: @Piotr Wargulak

@Maciej Grochalski I think this is a bug, but let’s wait for confirmation, here is PR. It comes down to confusion between inclusive end and exclusive end - when date was taken from ProcessingPeriod it was not converted to exclusive end.

@Maciej Grochalski I think this might wrong result.

I think the idea of 360day calendar comes down to simple fact: All months are 30 days. Therefore, the 31st does not exist, therefore anything that happens at 31st doesn’t exist and is not counted toward any metric.

So I think, the correct calculation of stock-out days in your example should be the same for both months - a 23 days. 24 days

BUT,
this is based on some talks with ChatGPT, which points me to financial calculation methods (ex.: A US Treasury bond that accrues interest from January 30th to February 1st will count 2 days, ignoring January 31st.).
We use 30day month, stock-out days + stock-present-days should equal 30, but maybe we need a confirmation from @Vitalliance David @Artur Lebiedziński.

QA: Before changes:

• 31-days-months when there was no stock available returns 30 stock-out days (which is correct)

• 30-days-months when there was no stock available returns 29 stock-out days (which is incorrect)

• Making Receive in a 31-days-month period at 13th day and Issue at 19th day results in 24 stock-out days

• Making Receive in a 30-days-month period at 13th day and Issue at 19th day results in 23 stock-out days

QA: After changes:

• 31-days-months when there was no stock available returns 30 stock-out days (which is correct)

• 30-days-months when there was no stock available returns 30 stock-out days (which is correct)

• Making Receive in a 31-days-month period at 13th day and Issue at 19th day results in 24 stock-out days

• Making Receive in a 30-days-month period at 13th day and Issue at 19th day results in 23 stock-out days

• Full February is counted as 30 days (which is correct)

It seems like the 29-days issue is not occurring anymore, but I’m not totally sure about underlined points, there are two different values which makes sense, because one month is longer, but at the other hand shouldn’t they be the same in our calculation method? @Piotr Wargulak what do you think about it?

I start verifying the change