Unit tests

[DyfanJones]

Design unit tests to improve robustness of package.

[DyfanJones]

As most classes connect to sagemaker's api mock test are required. From my understanding R has a framework mockery

R6 mockery example: https://github.com/r-lib/mockery/blob/380d81e1439969908a767e484939450b17b1b9ad/tests/testthat/test_stub.R#L197-L230

If this doesn't work then possibly set up a mock class for unit test similar to how this package works: https://github.com/frbl/OnlineSuperLearner/blob/8d36c4ae946690f53c125362c8081d1039ee2947/R/SMG.Mock.R

[DyfanJones]

Going forwards unit test/mock test will be raised individually testing out specific classes within R6sagemaker. This is to prevent the momentum of the project slowing down. (Apologises for any issues this causes)

[DyfanJones]

Create simple Mock class: https://github.com/DyfanJones/sagemaker-r-sdk/pull/14/files#diff-242c1a4b4f578945f62b2d3efad05545 to mimic R6 classes.

[DyfanJones]

Split Packages Requiring Unit tests:

• R6sagemaker.common
• R6sagemaker.local
• R6sagemaker.mlcore
• R6sagemaker.mlframework
• R6sagemaker.workflow
• R6sagemaker.debugger