Say I have an Epic that is estimated to take 3 sprints to do.
And the Epic is broken down into A to Z tasks/user stories.
Problem is, to do B, we need A, to do C we need B, etc.... And in sprint one, we only complete A to E,
and I do not think it can be classified as "Done/Done" within a sprint, as that functionality cannot be tested as it breaks existing functionality, what is the best practice for such a scenario?
1) Epic = Revamp of Super Calculator Functionality.
2) Calculator has Calculate A, Calculate B to Calculate Z Functionality and a final result.
3) You need to do Calculate A to do Calculate B, as Calculate B requires the result from Calculate A, etc until Z.
4) Existing calculator has A to Z, but their rules have all changed.
5) The final calculator result is wrong if only Calculate A to B are changed, as existing C will break.
6) They can be unit tested per unit, but cannot be checked in and tested on the ui by testers and cannot be defined as done, as the release should not include partial changes, as customers are using the calculator.
Such scenarios are affecting our burndown chart per sprint and bosses are complaining, hence this question.