Test_cases_to_reproduce_issues_24_25_27

Execute the Test cases to identify the issues. ( For more information, refer to the corresponding issues #24 (closed), #25 (closed), #27 (closed))

Before fixing, The test/graphdb_test.cpp should fail at 33e32683 , 33e32683 , 33e32683

The test/transaction_test.cpp should fail at 33e32683 and crash at 33e32683

If tests in transaction_test.cpp are not failing, then re-run the test cases several times until it fails.

In addition to the current test cases, it is recommended to verify the fix under a similar kind of scenario with at least 5 to 10 concurrent transactions.

After the fix, the test in graphdb_test.cpp may be removed.