Tried stack deletion but it is failed to delete the stack. And I have removed the some of testvm's manually before deleting the stack.
When I checked the test_resource it is in Delete failed status. So that the stack got struck in delete.
Could you please suggest me delete the stack.
Take a look at all the components of the stack. Take a look at the service logs for the failed stack deletion.
For example, if your stack has (or had) a Volume and an Instance, and there is disagreement between Nova and Cinder about the Volume's attachment status, then the Volume won't delete, and that causes the stack deletion to fail.