Testing helper package

[rigelrozanski]

Some of the functions such as IntEq and DecEq should be moved into an independent testing package within the sdk (probs within /tests) which contains all sorts of helpers to make writing tests in the SDK easier/quicker. In this package they should probably contain assert/require statements right in them.

quotes from #2236 (review)

Yeah cool - maybe it could be exported as a special testing-helpers package, I DO find these helper functions to be super useful / make writing tests less painful (for which we should be striving to do)
maybe a cleaner pattern would actually just be having pre-fab assert/require functions for some of the sdk primitives - therefor, we're not passing the outs from one function into the in's of the next function.

[ValarDragon]

We may only want this for types, since we probs don't want to introduce inter-module dependencies. I'm actually more in favor of a top-level internal package which contains such code, since we can then introduce more module's testing code easily without causing annoying import cycles.

[jackzampolin]

Don't think this blocks 1.0, but is this something you still would like done @rigelrozanski ?

[rigelrozanski]

not 1.0 but yes we still want this... adding good-first-issue tag