New method which is used to send outgoing email data
Added comment
Extract class that has responsibility for sending outgoing emails
Move OutgoingEmail to its own file and move tests too
Refactor tests
Inline method
New class for caching the email data to filesystem
Move class to its own file
Split out tests for EmailDataCache
Make methods private
Made test more specific and method private
Rename methods
EmailDataCache now has a much more simple interface