Added stacktach db api smoke tests

Added few positive smoke tests to test below stacktach db apis:
* Launches
* Exists
* Deletes

Change-Id: Idec6bb4ec166c31ebcc7b1175ca1e006e3026f79
Added stacky db api negative tests

Added stacky db api negative tests for:
* Launches
* Deletes
* Exists

Change-Id: I03fdee25496385b61bb22bee755ab3c16d48ebbd
Added more tests to stacky api

* Added few more smoke tests to stacky api
* Created an instance of stacky behavior in fixture

Change-Id: I52cbb323a300388926853a327d75b5d6f7a0fefe
Merge "Added stacky db api negative tests"
Merge "Added stacktach db api smoke tests"
Merge "Added more tests to stacky api"