please refactor this into multiple files
refactor this go program to use two classes Card, Hand and two use pointer receivers
Create a go test file hand_test.go to test the Hand struct according to go conventions. The tests must cover:                                                                                                                          
   Correct evaluation of different hand values.                                                                                                                                                                                          
   Comparison logic between two different hands.                                                                                                                                                                                       
   The 'best hand' selection logic from 7 cards. After writing the tests, provide the command to run these tests and  
   generate a test report including code coverage."