Add file replacement test:
Tests the file_replacing logic,
in all of its forms (create a file with contents A; create a file replacing that file with contents B;
open the file for read and make sure you get contents A; do the 'finish replacing' operation;
open the file for read and make sure you get contents B;
Add file replacement test: Tests the file_replacing logic, in all of its forms (create a file with contents A; create a file replacing that file with contents B; open the file for read and make sure you get contents A; do the 'finish replacing' operation; open the file for read and make sure you get contents B;