Lesson: 100 | Automatically Adjust Opportunity Close Dates Based on a Custom Range

User Story
Codes
Test Class

User Story

As a Salesforce Admin,
I want a method to automatically set the Close Date of Opportunities so that each Opportunity is n days ahead of the previous one,
So that I can ensure orderly and sequential opportunity Close Dates while following best practices.

Acceptance Criteria:

The solution must be implemented in a utility class named OpportunityUtility.
The method SetSequentialCloseDates(Integer NDays) should allow specifying the gap (n days) between the Close Dates of consecutive Opportunities.
The first Opportunity in the list should retain its original Close Date.
For each subsequent Opportunity in the list, the Close Date should be incremented by n days relative to the previous Opportunity.
The method should ensure that updates are only applied to Opportunities with non-null Close Dates and that the Opportunities are processed in ascending order of their current Close Date.