Create unit test file for datastore api
Add unit test class declaration and friend class it in DataStore
Update vcxproj files
Add method getAllTask()
Rearrange method declaration and definition for better readability
Add test for getAllTask
Storing stuff to switch branch
Move operation queue to transaction
Implement commit, rollback, push
Implement commit, rollback and push
Change return value of DataStore operations to void
Fix includes
Modify the instance getter of DataStore to public
Add active transaction member variable to DataStore
Add method notify to notify DataStore that a transaction is being committed
Add member variable: transaction stack
Modification to begin(): changes isServing to true and pushes the transaction made to the stack
Add const modifier to Post and PutOperation ctor
Add const modifier to post and put method of DataStore
Remove unnecessary space