Click on either button to add a new test. You will be asked to provide a name for the new test. After that, the following files will be created:
contracts-dbg/TESTNAME/ - the test contract directory. Each test must have its own directory.
contracts-dbg/TESTNAME/TESTNAME.t.sol - the main solidity file for the test.
contracts-dbg/TESTNAME/dbg.contract.json - sdbg config file for the test.