Modularize tests into separate files

[aldy505]

Currently there are only 2 files for the entire SDK tests and each of them got thousands lines of code. We should separate the tests by some chunk, to make it easy to read by others.

As a side note, I actually wanted to migrate Mocha and the mocha-step dependency we use to something more modern, but that would mean it might break some things in tests.

[prakashsvmx]

Sure. We will complete the ts migration. and work on migrating the tests.