Write Unit Tests for Docker container creation

[supra08]

Currently we don't have formal tests to ensure successful container creation while deploying applications. Writing unit tests for Gasper's Docker package will not only solve the above issue but will act as a sanity check when building new features on top of the existing ones. Tests are simple in Golang:- filename_test.go will run the tests for filename.go for every file in the same package. This article can be referred to for more information.